Metaphysics

Violations of Bell’s Inequality: Drawing Conclusions

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In the post on violations of Bell’s inequality, represented there by Mark Alford’s twin analogy, I pointed out that things did not seem to go very well for Einstein’s hope for physics, I did not draw any specific conclusions. Here I will consider the likely consequences, first by looking at the relationship of the experiments to Einstein’s position on causality and determinism, and second on their relationship to Einstein’s position on locality and action at a distance.

Einstein on Determinism

Einstein hoped for “facts” instead of probabilities. Everything should be utterly fixed by the laws, much like the position recently argued by Marvin Edwards in the comments here.

On the face of it, violations of Bell’s inequality rule this out, represented by the argument that if the twins had pre-existing determinate plans, it would be impossible for them to give the same answer less than 1/3 of the time when they are asked different questions. Bell however pointed out that it is possible to formulate a deterministic theory which would give similar probabilities at the cost of positing action at a distance (quoted here):

Moreover, a hidden variable interpretation of elementary quantum theory has been explicitly constructed. That particular interpretation has indeed a grossly non-local structure. This is characteristic, according to the result to be proved here, of any such theory which reproduces exactly the quantum mechanical predictions.

Nonetheless, I have set aside action at a distance to be discussed separately, and I would argue that we should accept the above surface appearance: the outcomes of quantum mechanical experiments are actually indeterministic. These probabilities represent something in the world, not merely something in our knowledge.

Why? In the first place, note that “reproduces exactly the quantum mechanical predictions” can be understood in two ways. A deterministic theory of that kind would say that because the details are unknown to us, we cannot know what is going to happen. But the details are there, and they in fact determine what is going to happen. There is still a difference on the object level between a world where the present fixes the future to a single possibility, and one in which the future is left open, as Aristotle supposed.

Of course there is no definitive proof here that we are actually in the situation with the open future, although the need for action at a distance in the alternative theory suggests that we are. Even apart from this, however, the general phenomena of quantum mechanics directly suggest that this is the situation. Even apart from violations of Bell’s inequality, quantum mechanics in general already looked exactly as we should have expected a world with an indeterminate future to look.

If this is the case, then Einstein was mistaken on this point, at least to this extent. But what about the deterministic aspect, which I mentioned at the end of this post, and which Schrödinger describes:

At all events it is an imagined entity that images the blurring of all variables at every moment just as clearly and faithfully as does the classical model its sharp numerical values. Its equation of motion too, the law of its time variation, so long as the system is left undisturbed, lags not one iota, in clarity and determinacy, behind the equations of motion of the classical model.

The answer is that this is deterministic not because the future, as we know it, is deterministic, but because it describes all of the possibilities at once. Thus in the case of the cat it includes both the cat living and the cat dying, which are two possible outcomes. It is “deterministic” only because once you have stated all of the alternatives, there is nothing left to say.

Why did Einstein want a deterministic theory? He openly admits that he does not have a convincing argument for it. It seems likely, however, that the fundamental motivation is the conviction that reality is intelligible. And an indeterministic world seems significantly less intelligible than a deterministic one. But this desire can in fact be satisfied by this second kind of “determinism”; thus Schrödinger calls it “one perfectly clear concept.”

In this respect, Einstein’s intuition was not mistaken. It is possible to give an intelligible account of the world, even a “deterministic” one, in this sense.

Einstein on Locality

Einstein also wanted to avoid “spooky action at a distance.” Admitting that the future is indeterminate, however, is not enough to avoid this conclusion. In Mark Alford’s twin analogy, it is not only pre-determined plans that fail, but also plans that involve randomness. Thus it first appears that the violations of Bell’s inequality absolutely require action at a distance.

If we follow my suggestion here, however, and consequently adopt Hugh Everett’s interpretation of quantum mechanics, then saying that there are multiple future possibilities implies the existence of multiple timelines. And if there are multiple timelines, violations of Bell’s inequality no longer necessarily imply action at a distance.

Why not? Consider the twin experiment with the assumption of indeterminacy and multiple timelines. Suppose that from the very beginning, there are two copies of each twin. The first copy of the first twin has the plan of responding to the three questions with “yes/yes/yes.” Likewise, the first copy of the second twin has the plan of responding to the three questions with, “yes/yes/yes.” In contrast, the second copy of each twin has the plan of responding with “no/no/no.”

Now we have four twins but the experimenter only sees two. So which ones does he see? There is nothing impossible about the following “rule”: if the twins are asked different questions, the experimenter sees the first copy of one of the twins, and the second copy of the other twin. Meanwhile, if the twins are asked the same question, the experimenter sees either the first copy of each twin, or the second copy of each twin. It is easy to see that if this is the case, the experimenter will see the twins agree, when they are asked the same question, and will see them disagree when they are asked different questions (thus agreeing less than 1/3 of the time in that situation.)

“Wait,” you will say. “If multiple timelines is just a way of describing a situation with indeterminism, and indeterminism is not enough to avoid action at a distance, how is it possible for multiple timelines to give a way out?”

From the beginning, the apparent “impossibility” of the outcome was a statistical impossibility, not a logical impossibility. Naturally this had to be the case, since if it were a logical impossibility, we could not have coherently described the actual outcomes. Thus we might imagine that David Hume would give this answer:

The twins are responding randomly to each question. By pure chance, they happened to agree the times they were asked the same question, and by pure chance they violated Bell’s inequality when they were asked different questions.

Since this was all a matter of pure chance, of course, if you do the experiment again tomorrow, it will turn out that all of the answers are random and they will agree and disagree 50% of the time on all questions.

And this answer is logically possible, but false. This account does not explain the correlation, but simply ignores it. In a similar way, the reason why indeterministic theories without action at a distance, but described as having a single timeline, cannot explain the results is that in order to explain the correlation, the outcomes of both sides need to be selected together, so to speak. But “without action at a distance” in this context simply means that they are not selected together. This makes the outcome statistically impossible.

In our multiple timelines version, in contrast, our “rule” above in effect selected the outcomes together. In other words, the guideline we gave regarding which pairs of twins the experimenter would meet, had the same effect as action at a distance.

How is all this an explanation? The point is that the particular way that timelines spread out when they come into contact with other things, in the version with multiple timelines, exactly corresponds to action at a distance, in the version without them. An indeterministic theory represented as having a single timeline and no action at a distance could be directly translated into a version with multiple timelines; but if we did that, this particular multiple timeline version would not have the rule that produces the correct outcomes. And on the other hand, if we start with the multiple timeline version that does have the rule, and translate it into a single timeline account, it will have action at a distance.

What does all this say about Einstein’s opinion about locality? Was he right, or was he wrong?

We might simply say that he was wrong, insofar as the actual situation can in fact be described as including action at a distance, even if it is not necessary to describe it in this way, since we can describe it with multiple timelines and without action at a distance. But to the degree that this suggests that Einstein made two mistakes, one about determinism and one about action at a distance, I think this is wrong. There was only one mistake, and it was the one about determinism. The fact is that as soon you speak of indeterminism at all, it becomes possible to speak of the world as having multiple timelines. So the question at that point is whether this is the “natural” description of the situation, where the natural description more or less means the best way to understand things, in which case the possibility of “action at a distance” is not an additional mistake on Einstein’s part, but rather it is an artifact of describing the situation as though there were only a single timeline.

You might say that there cannot be a better or worse way to understand things if two accounts are objectively equivalent. But this is wrong. Thus for example in general relativity it is probably possible to give an account where the earth has no daily rotation, and the universe is spinning around it every 24 hours. And this account is objectively equivalent to the usual account where the earth is spinning; exactly the same situation is being described, and nothing different is being asserted. And yet this account is weird in many ways, and makes it very hard to understand the universe. The far better and “natural” description is that the earth is spinning. Note, however, that this is an overall result; just looking out the window, you might have thought that saying that the universe is spinning is more natural. (Notice, however, that an even more natural account would be that neither the earth nor the universe is moving; it is only later in the day that you begin to figure out that one of them is moving.)

In a similar way, a single timeline account is originally more natural in the way a Ptolemaic account is more natural when you look out the window. But I would argue that in a similar way, the multiple timeline account, without action at a distance, is ultimately the more natural one. The basic reason for this is that there is no Newtonian Absolute Time. The consequence is that if we speak of “future possibilities,” they cannot be future possibilities for the entire universe at once. They will be fairly localized future possibilities: e.g. there might be more than one possible text for the ending to this blog post, which has not yet been written, and those possibilities are originally possibilities for what happens here in this room, not for the rest of the universe. These future alternatives will naturally result in future possibilities for other parts of the world, but this will happen “slowly,” so to speak (namely if one wishes to speak of the speed of light as slow!) This fits well with the idea of multiple timelines, since there will have to be some process where these multiple timelines come into contact with the rest of the world, much as with our “rule” in the twin experiment. On the other hand, it does not fit so well with a single timeline account of future possibilities, since one is forced (by the terms of the account) to imagine that when a choice among possibilities is made, it is made for the entire universe at once, which appears to require Newton’s Absolute Time.

This suggests that Einstein was basically right about action at a distance, and wrong about determinism. But the intuition that motivated him to embrace both positions, namely that the universe should be intelligible, was sound.

Open Past

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Suppose that Aristotle was right, and the future is open. What would things be like in detail?

There are many ways things could go, so for concreteness let’s assume that (in some local area) there are approximately 100 possibilities for the next second, and approximately 100 x 100, or 10,000 possibilities for the next two seconds.

Then the question arises: do some of the two-second outcomes have overlapping paths? In other words, suppose we take the first option in the first second. Are all of the outcomes we can reach different from all of the outcomes we could reach if we took the second option in the first second?

It is at least plausible that some overlapping paths can exist. For example, something might swerve to the left in the first second, and then to the right in the second second, ending up just where it would have been if it had swerved to the right in the first second and to the left in the second. Let’s suppose it turns out this way. Thus we have situation A and time A, and situation B and time B, with a first and second path, both of which lead from situation A at time A, to situation B at time B.

When we get to situation B, what does the world look like? In particular, if someone is in situation B and says, “let’s look at the world and figure out what just happened,” what does it look like? Consider three different accounts:

  1. It looks like situation B except also that it looks like we took the first path
  2. It looks like situation B except also that it looks like we took the second path
  3. It looks like situation B, and we can’t tell which path was taken

The problem is evident. These are three different situations. If things currently look different, the situation is different. So these cannot possibly all be descriptions of situation B. And in particular, only the third is a reasonable description of the situation we should expect. We have set up the situation so that there is no difference in our current situation, whether the first or second path was taken. So of course in situation B it will be impossible to know which path was taken.

But what does that look like, exactly? “We don’t know” is not a description of a situation, but a description of our state of knowledge. What is it about situation B that makes it impossible to tell which path was taken? What happens if you describe the situation as exactly as possible, and then explain why that “exact” description still does not determine which path was taken?

Consider again Schrödinger’s confusion about his cat. The reason why the notion of “bluriness” came up at all was not merely that the wave equation seems to describe something blurred, but also because the actual results of experiments suggest that something blurred took place. Thus for example in double-slit experiments, interference patterns suggest that something is going through both slits at once, while if detectors are added to determine what, if anything, is going through the slits, one seems to find that only one slit is used at a time, and the interference pattern goes away.

This fits the above description of situation A and situation B  almost perfectly. In the double slit experiment, there are two paths that could be taken to arrive at the same outcome. But that “same outcome” is not one in which it looks like the first path was taken, nor one in which it looks like the second path was taken, but one in which the outcome’s relationship to the path appears to be confused. And on the other hand, if we can tell which path was taken, as we can when we add detectors, there is no such confusion, because the outcomes no longer overlap; the outcome where the first detector registers is not the same as an outcome where the second detector registers.

In this sense, quantum theory is simply the situation where Aristotle was right about the indeterminacy of the future, with the minor addition that it turned out to be possible to get to the same future by more than route.

Note, however, that this implies the worrisome outcome that I suggested in that post. Just as the future is indeterminate, so is the past. Just as the present has many possible future outcomes, there are many past paths that could have resulted in the present.

Schrödinger’s Cat

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Erwin Schrödinger describes the context for his thought experiment with a cat:

The other alternative consists of granting reality only to the momentarily sharp determining parts – or in more general terms to each variable a sort of realization just corresponding to the quantum mechanical statistics of this variable at the relevant moment.

That it is in fact not impossible to express the degree and kind of blurring of all variables in one perfectly clear concept follows at once from the fact that Q.M. as a matter of fact has and uses such an instrument, the so-called wave function or psi-function, also called system vector. Much more is to be said about it further on. That it is an abstract, unintuitive mathematical construct is a scruple that almost always surfaces against new aids to thought and that carries no great message. At all events it is an imagined entity that images the blurring of all variables at every moment just as clearly and faithfully as does the classical model its sharp numerical values. Its equation of motion too, the law of its time variation, so long as the system is left undisturbed, lags not one iota, in clarity and determinacy, behind the equations of motion of the classical model. So the latter could be straight-forwardly replaced by the psi-function, so long as the blurring is confined to atomic scale, not open to direct control. In fact the function has provided quite intuitive and convenient ideas, for instance the “cloud of negative electricity” around the nucleus, etc. But serious misgivings arise if one notices that the uncertainty affects macroscopically tangible and visible things, for which the term “blurring” seems simply wrong. The state of a radioactive nucleus is presumably blurred in such a degree and fashion that neither the instant of decay nor the direction, in which the emitted alpha-particle leaves the nucleus, is well-established. Inside the nucleus, blurring doesn’t bother us. The emerging particle is described, if one wants to explain intuitively, as a spherical wave that continuously emanates in all directions and that impinges continuously on a surrounding luminescent screen over its full expanse. The screen however does not show a more or less constant uniform glow, but rather lights up at one instant at one spot – or, to honor the truth, it lights up now here, now there, for it is impossible to do the experiment with only a single radioactive atom. If in place of the luminescent screen one uses a spatially extended detector, perhaps a gas that is ionised by the alpha-particles, one finds the ion pairs arranged along rectilinear columns, that project backwards on to the bit of radioactive matter from which the alpha-radiation comes (C.T.R. Wilson’s cloud chamber tracks, made visible by drops of moisture condensed on the ions).

One can even set up quite ridiculous cases. A cat is penned up in a steel chamber, along with the following device (which must be secured against direct interference by the cat): in a Geiger counter there is a tiny bit of radioactive substance, so small, that perhaps in the course of the hour one of the atoms decays, but also, with equal probability, perhaps none; if it happens, the counter tube discharges and through a relay releases a hammer which shatters a small flask of hydrocyanic acid. If one has left this entire system to itself for an hour, one would say that the cat still lives if meanwhile no atom has decayed. The psi-function of the entire system would express this by having in it the living and dead cat (pardon the expression) mixed or smeared out in equal parts.

It is typical of these cases that an indeterminacy originally restricted to the atomic domain becomes transformed into macroscopic indeterminacy, which can then be resolved by direct observation. That prevents us from so naively accepting as valid a “blurred model” for representing reality. In itself it would not embody anything unclear or contradictory. There is a difference between a shaky or out-of-focus photograph and a snapshot of clouds and fog banks.

We see here the two elements described at the end of this earlier post. The psi-function is deterministic, but there seems to be an element of randomness when someone comes to check on the cat.

Hugh Everett amusingly describes a similar experiment performed on human beings (but without killing anyone):

Isolated somewhere out in space is a room containing an observer, A, who is about to perform a measurement upon a system S. After performing his measurement he will record the result in his notebook. We assume that he knows the state function of S (perhaps as a result of previous measurement), and that it is not an eigenstate of the measurement he is about to perform. A, being an orthodox quantum theorist, then believes that the outcome of his measurement is undetermined and that the process is correctly described by Process 1 [namely a random determination caused by measurement].

In the meantime, however, there is another observer, B, outside the room, who is in possession of the state function of the entire room, including S, the measuring apparatus, and A, just prior to the measurement. B is only interested in what will be found in the notebook one week hence, so he computes the state function of the room for one week in the future according to Process 2 [namely the deterministic  wave function]. One week passes, and we find B still in possession of the state function of the room, which this equally orthodox quantum theorist believes to be a complete description of the room and its contents. If B’s state function calculation tells beforehand exactly what is going to be in the notebook, then A is incorrect in his belief about the indeterminacy of the outcome of his measurement. We therefore assume that B’s state function contains non-zero amplitudes over several of the notebook entries.

At this point, B opens the door to the room and looks at the notebook (performs his observation.) Having observed the notebook entry, he turns to A and informs him in a patronizing manner that since his (B’s) wave function just prior to his entry into the room, which he knows to have been a complete description of the room and its contents, had non-zero amplitude over other than the present result of the measurement, the result must have been decided only when B entered the room, so that A, his notebook entry, and his memory about what occurred one week ago had no independent objective existence until the intervention by B. In short, B implies that A owes his present objective existence to B’s generous nature which compelled him to intervene on his behalf. However, to B’s consternation, A does not react with anything like the respect and gratitude he should exhibit towards B, and at the end of a somewhat heated reply, in which A conveys in a colorful manner his opinion of B and his beliefs, he rudely punctures B’s ego by observing that if B’s view is correct, then he has no reason to feel complacent, since the whole present situation may have no objective existence, but may depend upon the future actions of yet another observer.

Schrödinger’s problem was that the wave equation seems to describe something “blurred,” but if we assume that is because something blurred exists, it seems to contradict our experience which is of something quite distinct: a live cat or a dead cat, but not something in between.

Everett proposes that his interpretation of quantum mechanics is able to resolve this difficulty. After presenting other interpretations, he proposes his own (“Alternative 5”):

Alternative 5: To assume the universal validity of the quantum description, by the complete abandonment of Process 1 [again, this was the apparently random measurement process]. The general validity of pure wave mechanics, without any statistical assertions, is assumed for all physical systems, including observers and measuring apparata. Observation processes are to be described completely by the state function of the composite system which includes the observer and his object-system, and which at all times obeys the wave equation (Process 2).

…

It is evident that Alternative 5 is a theory of many advantages. It has the virtue of logical simplicity and it is complete in the sense that it is applicable to the entire universe. All processes are considered equally (there are no “measurement processes” which play any preferred role), and the principle of psycho-physical parallelism is fully maintained. Since the universal validity of the state function is asserted, one can regard the state functions themselves as the fundamental entities, and one can even consider the state function of the whole universe. In this sense this theory can be called the theory of the “universal wave function,” since all of physics is presumed to follow from this function alone. There remains, however, the question whether or not such a theory can be put into correspondence with our experience.

This present thesis is devoted to showing that this concept of a universal wave mechanics, together with the necessary correlation machinery for its interpretation, forms a logically self consistent description of a universe in which several observers are at work.

Ultimately, Everett’s response to Schrödinger is that the cat is indeed “blurred,” and that this never goes away. When someone checks on the cat, the person checking is also “blurred,” becoming a composite of someone seeing a dead cat and someone seeing a live cat. However, these are in effect two entirely separate worlds, one in which someone sees a live cat, and one in which someone sees a dead cat.

Everett mentions “the necessary correlation machinery for its interpretation,” because a mathematical theory of physics as such does not necessarily say that anyone should see anything in particular. So for example when Newton when says that there is a gravitational attraction between masses inversely proportional to the square of their distance, what exactly should we expect to see, given that? Obviously there is no way to answer this without adding something, and ultimately we need to add something non-mathematical, namely something about the way our experiences work.

I will not pretend to judge whether or not Everett does a good job defending his position. There is an interesting point here, whether or not his defense is ultimately a good one. “Orthodox” quantum mechanics, as Everett calls it, only gives statistical predictions about the future, and as long as nothing is added to the theory, it implies that deterministic predictions are impossible. It follows that if the position in our last post, on an open future, was correct, it must be possible to explain the results of quantum mechanics in terms of many worlds or multiple timelines. And I do not merely mean that we can give the same predictions with a one-world account or with a many world account. I mean that there must be a many-world account such that its contents are metaphysically identical to the contents of a one-world account with an open future.

This would nonetheless leave undetermined the question of what sort of account would be most useful to us in practice.

Open Future

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Let’s return for a moment to the question at the end of this post. I asked, “What happens if the future is indeterminate? Would not the eternalist position necessarily differ from the presentist one, in that case?”

Why necessarily different? The argument in that post was that eternalism and presentism are different descriptions of the same thing, and that we see the sameness by noting the sameness of relations between the elements of the description. But if the future is open, as Aristotle supposed, it is hard to see how we can maintain this. Aristotle says that the present is open to either having the sea battle tomorrow or not having it. With an eternalist view, the sea battle is “already there” or it is not. So in Aristotle’s view, the present has an open relationship to both possibilities. But the eternalist view seems to be truly open only to the possibility that will actually happen. We no longer have the same set of relationships.

Notice the problem. When I attempted to equate eternalism and presentism, I implicitly assumed that determinism is true. There were only three states of the universe, beginning, middle, and end. If determinism is false, things are different. There might be beginning, middle, and two potential ends. Perhaps there is a sea battle in one of the potential ends, and no sea battle in the other.

This suggests a solution to our conundrum, however. Even the presentist description in that post was inconsistent with an open future. If there is only one possible end, the future is not open, even if we insist that the unique possible end “currently doesn’t exist.” The problem then was not eternalism as such, but the fact that we started out with a determinist description of the universe. This strongly suggests that if my argument about eternalism and presentism was correct, we should be able to formulate eternalist and presentist descriptions of an open future which will be equivalent. But both will need to be different from the fixed “beginning-middle-end” described in that post.

We can simply take Aristotle’s account as the account of presentism with an open future. How can we give an eternalist account of the same thing? The basic requirement will be that the relationship between the present and the future needs to be the same in both accounts. Now in Aristotle’s account, the present has the same relationship to two different possibilities: both of them are equally possible. So to get a corresponding eternalist account, we need the present to be equally related to two futures that correspond to the two possiblities in the presentist account. I do not say “two possible futures,” but “two futures,” precisely because the account is eternalist.

The careful reader will already understand the account from the above, but let us be more explicit. The eternalist account that corresponds to the presentist account with an open future has multiple timelines, all of which “exist”, in the eternalist sense. The reader will no doubt be familiar with the idea of multiple timelines, at least from time travel fiction. In a similar way, the eternalist reworking of Aristotle’s position is that there is a timeline where the sea battle takes place, and another timeline where the sea battle does not take place. In this view, both of them “actually” happen. But even in this view, an observer in the middle location will have to say, “I do not, and cannot, know whether the sea battle will take place or not,” just as in Aristotle’s view. For the observer cannot traverse both timelines at once. From his point of view, he will take only one, but since his relationship to the two possibilities (or actualities) is the same, it is indeterminate which one it will be.

Even if one cannot prove my account of equivalence to be wrong, the reader may worry. Time travel fiction frequently seems incoherent, and this suggests that any view with multiple timelines may also be incoherent. But this potential incoherence supports the equivalence, rather than subtracting from it. For as we noted in the post on Aristotle, there is a definite appearance of incoherence in his position. It is not even clear how his view is logically possible. So it would not be surprising, but quite natural, if views which are intended to be equivalent to his position are also not clearly coherent. Nonetheless, the multiple timelines description does have some logical advantage over Aristotle’s position, in the sense that “the sea battle will take place in timeline A” does not even appear to contradict “the sea battle will not take place in timeline B.”

Aristotle on Future Contingents

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In Chapter 9 of On Interpretation, Aristotle argues that at least some statements about the future need to be exempted from the principle of Excluded Middle:

In the case of that which is or which has taken place, propositions, whether positive or negative, must be true or false. Again, in the case of a pair of contradictories, either when the subject is universal and the propositions are of a universal character, or when it is individual, as has been said,’ one of the two must be true and the other false; whereas when the subject is universal, but the propositions are not of a universal character, there is no such necessity. We have discussed this type also in a previous chapter.

When the subject, however, is individual, and that which is predicated of it relates to the future, the case is altered. For if all propositions whether positive or negative are either true or false, then any given predicate must either belong to the subject or not, so that if one man affirms that an event of a given character will take place and another denies it, it is plain that the statement of the one will correspond with reality and that of the other will not. For the predicate cannot both belong and not belong to the subject at one and the same time with regard to the future.

Thus, if it is true to say that a thing is white, it must necessarily be white; if the reverse proposition is true, it will of necessity not be white. Again, if it is white, the proposition stating that it is white was true; if it is not white, the proposition to the opposite effect was true. And if it is not white, the man who states that it is making a false statement; and if the man who states that it is white is making a false statement, it follows that it is not white. It may therefore be argued that it is necessary that affirmations or denials must be either true or false.

Now if this be so, nothing is or takes place fortuitously, either in the present or in the future, and there are no real alternatives; everything takes place of necessity and is fixed. For either he that affirms that it will take place or he that denies this is in correspondence with fact, whereas if things did not take place of necessity, an event might just as easily not happen as happen; for the meaning of the word ‘fortuitous’ with regard to present or future events is that reality is so constituted that it may issue in either of two opposite directions. Again, if a thing is white now, it was true before to say that it would be white, so that of anything that has taken place it was always true to say ‘it is’ or ‘it will be’. But if it was always true to say that a thing is or will be, it is not possible that it should not be or not be about to be, and when a thing cannot not come to be, it is impossible that it should not come to be, and when it is impossible that it should not come to be, it must come to be. All, then, that is about to be must of necessity take place. It results from this that nothing is uncertain or fortuitous, for if it were fortuitous it would not be necessary.

The argument here is that if it is already true, for example, that I will eat breakfast tomorrow, then I will necessarily eat breakfast tomorrow, and there is no option about this and no ability of anything to prevent it. Aristotle is here taking it for granted that some things about the future are uncertain, and is using this as a reductio against the position that such claims can be already true. He goes on to give additional reasons for the same thing:

Again, to say that neither the affirmation nor the denial is true, maintaining, let us say, that an event neither will take place nor will not take place, is to take up a position impossible to defend. In the first place, though facts should prove the one proposition false, the opposite would still be untrue. Secondly, if it was true to say that a thing was both white and large, both these qualities must necessarily belong to it; and if they will belong to it the next day, they must necessarily belong to it the next day. But if an event is neither to take place nor not to take place the next day, the element of chance will be eliminated. For example, it would be necessary that a sea-fight should neither take place nor fail to take place on the next day.

These awkward results and others of the same kind follow, if it is an irrefragable law that of every pair of contradictory propositions, whether they have regard to universals and are stated as universally applicable, or whether they have regard to individuals, one must be true and the other false, and that there are no real alternatives, but that all that is or takes place is the outcome of necessity. There would be no need to deliberate or to take trouble, on the supposition that if we should adopt a certain course, a certain result would follow, while, if we did not, the result would not follow. For a man may predict an event ten thousand years beforehand, and another may predict the reverse; that which was truly predicted at the moment in the past will of necessity take place in the fullness of time.

Further, it makes no difference whether people have or have not actually made the contradictory statements. For it is manifest that the circumstances are not influenced by the fact of an affirmation or denial on the part of anyone. For events will not take place or fail to take place because it was stated that they would or would not take place, nor is this any more the case if the prediction dates back ten thousand years or any other space of time. Wherefore, if through all time the nature of things was so constituted that a prediction about an event was true, then through all time it was necessary that that should find fulfillment; and with regard to all events, circumstances have always been such that their occurrence is a matter of necessity. For that of which someone has said truly that it will be, cannot fail to take place; and of that which takes place, it was always true to say that it would be.

Yet this view leads to an impossible conclusion; for we see that both deliberation and action are causative with regard to the future, and that, to speak more generally, in those things which are not continuously actual there is potentiality in either direction. Such things may either be or not be; events also therefore may either take place or not take place. There are many obvious instances of this. It is possible that this coat may be cut in half, and yet it may not be cut in half, but wear out first. In the same way, it is possible that it should not be cut in half; unless this were so, it would not be possible that it should wear out first. So it is therefore with all other events which possess this kind of potentiality. It is therefore plain that it is not of necessity that everything is or takes place; but in some instances there are real alternatives, in which case the affirmation is no more true and no more false than the denial; while some exhibit a predisposition and general tendency in one direction or the other, and yet can issue in the opposite direction by exception.

Now that which is must needs be when it is, and that which is not must needs not be when it is not. Yet it cannot be said without qualification that all existence and non-existence is the outcome of necessity. For there is a difference between saying that that which is, when it is, must needs be, and simply saying that all that is must needs be, and similarly in the case of that which is not. In the case, also, of two contradictory propositions this holds good. Everything must either be or not be, whether in the present or in the future, but it is not always possible to distinguish and state determinately which of these alternatives must necessarily come about.

Let me illustrate. A sea-fight must either take place to-morrow or not, but it is not necessary that it should take place to-morrow, neither is it necessary that it should not take place, yet it is necessary that it either should or should not take place to-morrow. Since propositions correspond with facts, it is evident that when in future events there is a real alternative, and a potentiality in contrary directions, the corresponding affirmation and denial have the same character.

This is the case with regard to that which is not always existent or not always nonexistent. One of the two propositions in such instances must be true and the other false, but we cannot say determinately that this or that is false, but must leave the alternative undecided. One may indeed be more likely to be true than the other, but it cannot be either actually true or actually false. It is therefore plain that it is not necessary that of an affirmation and a denial one should be true and the other false. For in the case of that which exists potentially, but not actually, the rule which applies to that which exists actually does not hold good. The case is rather as we have indicated.

Basically, then, there are two arguments. First there is the argument that if statements about the future are already true, the future is necessary. If a sea battle will take place tomorrow, it will necessarily take place. Second, there is the argument that this excludes deliberation. If a sea battle will take place tomorrow, then it will necessarily take place, and no place remains for deliberation and decision about whether to fight the sea battle. Whether you decide to fight or not, it will necessarily take place.

Unfortunately for Aristotle, both arguments fail. Consider the first argument about necessity. Aristotle’s example is that “if it is true to say that a thing is white, it must necessarily be white.” But this is hypothetical necessity, not absolute necessity. A thing must be white if it is true that is white, but that does not mean that “it must be white, period.” Thus for example I have a handkerchief, and it happens to be white. If it is true that it is white, then it must be white. But it would be false to simply say, “My handkerchief is necessarily white.” Since I can dye it other colors, obviously it is not simply necessary for it to be white.

In a similar way, of course it is true that if a sea battle will take place, it will take place. It does not follow at all that “it will necessarily take place, period.”

Again, consider the second argument, that deliberation would be unnecessary. Aristotle makes the point that deliberation is causative with respect to the future. But gravity is also causative with respect to the future, as for example when gravity causes a cup to fall from a desk. It does not follow either that the cup must be able not to fall, nor that gravity is unnecessary. In a similar way, a sea battle takes place because certain people deliberated and decided to fight. If it was already true that it was going to take place, then it also already true that they were going to decide to fight. It does not follow that their decision was unnecessary.

Consider the application to gravity. It is already true that if the cup is knocked from the desk, it will fall. It does not follow that gravity will not cause the fall: in fact, it is true precisely because gravity will cause the fall. In a similar way, if it true that the battle will take place, it is true because the decision will be made.

This earlier discussion about determinism is relevant to this point. Asserting that there is a definite outcome that our deliberations will arrive at, in each case, goes against our experience in no way. The feeling of “free will,” in any case, has a different explanation, whether or not determinism is true.

On the other hand, there is also no proof that there is such a determinate outcome, even if in some cases there are things that would suggest it. What happens if in fact there is nothing ensuring one outcome rather than another?

Here we could make a third argument on Aristotle’s behalf, although he did not make it himself. If the present is truly open to alternative outcomes, then it seems that nothing exists that could make it be true that “a sea battle will take place,” and false that “a sea battle will not take place.” Presumably if a statement is true, there must be something in reality which is the cause of the statement’s truth. Now there does not seem to be anything in reality, in this scenario, which could be a cause of truth. Therefore it does not seem that either alternative could be true, and Aristotle would seem to be right.

I will not attempt to refute this argument at this point, but I will raise two difficulties. First of all, it is not clear that his claim is even coherent. Aristotle says that “either there will be a sea battle or there will not be,” is true, but that “there will be a sea battle” is not true, and “there will not be a sea battle” is not true. This does not seem to be logically consistent, and it is not clear that we can even understand what is being said. I will not push this objection too hard, however, lest I be accused of throwing stones from a glass house.

Second, the argument that there is nothing in reality that could cause the truth of a statement might apply to the past as well as to the future. There is a tree outside my window right now. What was in that place exactly 100 million years ago to this moment? It is not obvious that there is anything in the present world which could be the cause of the truth of any statement about this. One might object that the past is far more determinate than the future. There are plenty of things in the present world that might be the cause of the truth of the statement, “World War II actually happened.” It is hard to see how you could possibly have arrived at the present world without it, and this “necessity” of World War II in order to arrive at the present world could be the cause of truth. The problem is that there is still no proof that this is universal. Once things are far enough in past, like 100 million years, perhaps minor details become indeterminate. Will Aristotle really want to conclude that some statements about the past are neither true nor false?

I will more or less leave things here without resolving them in this post, although I will give a hint (without proof at this time) regarding the truth of the matter. It turns out that quantum mechanics can be interpreted in two ways. In one way, it is a deterministic theory, and in this way it is basically time reversible. The present fully determines the past, but it equally fully determines the future. Interpreted in another way, it is an indeterministic theory which leaves the future uncertain. But understood in this way, it also leaves the past uncertain.

Ontological Becoming

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Most likely I will follow up on the chain of thought started in the last post, at some point. At the moment, however, this post (and possibly a few more) will be clarifying some earlier questions.

In this post on causality, I said that the discussion of “true ontological becoming” was not really relevant, and it was not. Nonetheless, there is no harm in explaining the point. Atheism and the City is attempting to maintain a position somewhat like that of Parmenides. The theory of relativity leads in a fairly natural way to a view which includes something along the lines of a four dimensional block universe, or an “eternalist” view. Things appear to change, but as Parmenides claims, this is an illusion. Everything already exists. This might be somewhat different from Parmenides insofar as Parmenides seems to assert that differences are pure illusion, while the eternalist view usually says that when you see different times, you are seeing various aspects of the eternally existing reality.

I said in the post on causality that eternalism vs. presentism is an example of a Kantian dichotomy; both positions , to the degree that they are opposed, rest on a misunderstanding of the relationship between the mind and reality. I will not try to prove this in a fully general way at the moment, but show how this is true with a simplified model of reality.

In the first place, if we want to take these positions seriously, neither one should be understood as saying that we do not have the experiences that we do have. You might think that eternalism would deny that we ever experience things changing. But that is not what Atheism and the City (and other eternalists) actually say:

On my view of causality, if you threw a brick at a glass window it would shatter, if you jumped in front of a speeding train you’d be smashed to death by it. The difference between my view of causality vs the typical view is that on my view causes do not bring their effects into existence in the sense of true ontological becoming.

There is no denial of our usual experiences, but rather it is affirmed that we have them. It is the claim about the true nature of things that is different from the claim of the presentist. Both positions admit that we see things like bricks breaking windows and train destroying objects that they hit.

Consider two simplified universes: an eternalist one and a presentist one. In the eternalist universe, suppose that there are three times, a beginning, a middle, and an end, and an observer that watches time pass and knows the nature of their universe. Things appear to change, but they deny that there is “true ontological becoming.” All times, according to them, exist, but they experience them as a sequence.

In the presentist universe, on the other hand, there are still three times, but they exist only in sequence. The observer here passes through time and knows that they do so.

My position is that these are two different descriptions of precisely the same thing, and asking which universe you are in is like asking whether a table is on the right or on the left. Why is this the case? The basic reason is that the network of relationships described in the (supposedly) two situations is the same, and since this network is form, the form or nature of these two situations is entirely the same.

Let’s look at this in more detail by considering the points where the positions supposedly disagree. Let’s take our observers in the middle of the time period. They try to describe their disagreement:

Eternalist: I appear to be in the middle period, but really I am in all periods. The middle currently appears to exist, but in fact beginning, middle, and end exist.

Presentist: The middle period alone currently exists. The beginning and end do not, although the beginning once existed, and the end will exist later.

Do they disagree about whether the beginning exists or not? The eternalist might say, yes, we disagree. I think the beginning currently exists, the presentist thinks that it does not. But notice “currently.” Does the eternalist think that the beginning exists at the middle time? Of course not: they think it exists at its own time. So why do they say “currently”, when we are discussing their observations at the middle time? Basically, the eternalist is saying that from an abstract point of view, their universe contains all the times, and they are describing this point of view by saying “currently.” The presentist, however, is saying that from a concrete point of view, namely the middle time, only the middle time is present. The presentist is not denying that if you look at the times in the abstract, you cannot tell which one is present; “telling which one is present” is precisely to view them concretely.

Our disputants will insist:

Eternalist: According to the true nature of things, the beginning exists, period. Don’t talk about abstract or concrete or whatever.

Presentist: According to the true nature of things, the beginning does not exist, period. Don’t talk about abstract or concrete or whatever.

The first problem with this is obvious, and applies to both positions. Both positions here seem to want to take “exist” as absolute rather than relative, and this cannot be done.

There is a second problem which applies to the presentist position in particular, as described here. Consider another universe, one with only one time and one observer. How is this universe different from the presentist universe with three times? In each of them, the observer claims that there is no past and no future. Our presentist needs to say that “there really was a past” in order to distinguish their position from that of the single time universe. But what can that possibly mean, if the past is literally nothing at all?

In any case, if it means anything at all, “the past that used to exist” in the presentist description has the same relationship to the middle time that “the past that actually exists” in the eternalist description has to the middle time. As I have been saying, the two descriptions have the same elements, and the same set of relationships. They are descriptions of precisely the same reality.

The disagreement, in other words, is not a disagreement about reality, but about which point of view is the “true” one. But points of view are just that, points of view, and the thing can be seen from each. It is just not the case that one is true and the other false.

This of course used a simplified model, and things in the real world are more complicated. For example, what happens if the future is indeterminate? Would not the eternalist position necessarily differ from the presentist one, in that case?

Employer and Employee Model of Human Psychology

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This post builds on the ideas in the series of posts on predictive processing and the followup posts, and also on those relating truth and expectation. Consequently the current post will likely not make much sense to those who have not read the earlier content, or to those that read it but mainly disagreed.

We set out the model by positing three members of the “company” that constitutes a human being:

The CEO. This is the predictive engine in the predictive processing model.

The Vice President. In the same model, this is the force of the historical element in the human being, which we used to respond to the “darkened room” problem. Thus for example the Vice President is responsible for the fact that someone is likely to eat soon, regardless of what they believe about this. Likewise, it is responsible for the pursuit of sex, the desire for respect and friendship, and so on. In general it is responsible for behaviors that would have been historically chosen and preserved by natural selection.

The Employee. This is the conscious person who has beliefs and goals and free will and is reflectively aware of these things. In other words, this is you, at least in a fairly ordinary way of thinking of yourself. Obviously, in another way you are composed from all of them.

Why have we arranged things in this way? Descartes, for example, would almost certainly disagree violently with this model. The conscious person, according to him, would surely be the CEO, and not an employee. And what is responsible for the relationship between the CEO and the Vice President? Let us start with this point first, before we discuss the Employee. We make the predictive engine the CEO because in some sense this engine is responsible for everything that a human being does, including the behaviors preserved by natural selection. On the other hand, the instinctive behaviors of natural selection are not responsible for everything, but they can affect the course of things enough that it is useful for the predictive engine to take them into account. Thus for example in the post on sex and minimizing uncertainty, we explained why the predictive engine will aim for situations that include having sex and why this will make its predictions more confident. Thus, the Vice President advises certain behaviors, the CEO talks to the Vice President, and the CEO ends up deciding on a course of action, which ultimately may or may not be the one advised by the Vice President.

While neither the CEO nor the Vice President is a rational being, since in our model we place the rationality in the Employee, that does not mean they are stupid. In particular, the CEO is very good at what it does. Consider a role playing video game where you have a character that can die and then resume. When someone first starts to play the game, they may die frequently. After they are good at the game, they may die only rarely, perhaps once in many days or many weeks. Our CEO is in a similar situation, but it frequently goes 80 years or more without dying, on its very first attempt. It is extremely good at its game.

What are their goals? The CEO basically wants accurate predictions. In this sense, it has one unified goal. What exactly counts as more or less accurate here would be a scientific question that we probably cannot resolve by philosophical discussion. In fact, it is very possible that this would differ in different circumstances: in this sense, even though it has a unified goal, it might not be describable by a consistent utility function. And even if it can be described in that way, since the CEO is not rational, it does not (in itself) make plans to bring about correct predictions. Making good predictions is just what it does, as falling is what a rock does. There will be some qualifications on this, however, when we discuss how the members of the company relate to one another.

The Vice President has many goals: eating regularly, having sex, having and raising children, being respected and liked by others, and so on. And even more than in the case of the CEO, there is no reason for these desires to form a coherent set of preferences. Thus the Vice President might advise the pursuit of one goal, but then change its mind in the middle, for no apparent reason, because it is suddenly attracted by one of the other goals.

Overall, before the Employee is involved, human action is determined by a kind of negotiation between the CEO and the Vice President. The CEO, which wants good predictions, has no special interest in the goals of the Vice President, but it cooperates with them because when it cooperates its predictions tend to be better.

What about the Employee? This is the rational being, and it has abstract concepts which it uses as a formal copy of the world. Before I go on, let me insist clearly on one point. If the world is represented in a certain way in the Employee’s conceptual structure, that is the way the Employee thinks the world is. And since you are the Employee, that is the way you think the world actually is. The point is that once we start thinking this way, it is easy to say, “oh, this is just a model, it’s not meant to be the real thing.” But as I said here, it is not possible to separate the truth of statements from the way the world actually is: your thoughts are formulated in concepts, but they are thoughts about the way things are. Again, all statements are maps, and all statements are about the territory.

The CEO and the Vice President exist as soon a human being has a brain; in fact some aspects of the Vice President would exist even before that. But the Employee, insofar as it refers to something with rational and self-reflective knowledge, takes some time to develop. Conceptual knowledge of the world grows from experience: it doesn’t exist from the beginning. And the Employee represents goals in terms of its conceptual structure. This is just a way of saying that as a rational being, if you say you are pursuing a goal, you have to be able to describe that goal with the concepts that you have. Consequently you cannot do this until you have some concepts.

We are ready to address the question raised earlier. Why are you the Employee, and not the CEO? In the first place, the CEO got to the company first, as we saw above. Second, consider what the conscious person does when they decide to pursue a goal. There seems to be something incoherent about “choosing a goal” in the first place: you need a goal in order to decide which means will be a good means to choose. And yet, as I said here, people make such choices anyway. And the fact that you are the Employee, and not the CEO, is the explanation for this. If you were the CEO, there would indeed be no way to choose an end. That is why the actual CEO makes no such choice: its end is already determinate, namely good predictions. And you are hired to help out with this goal. Furthermore, as a rational being, you are smarter than the CEO and the Vice President, so to speak. So you are allowed to make complicated plans that they do not really understand, and they will often go along with these plans. Notably, this can happen in real life situations of employers and employees as well.

But take an example where you are choosing an end: suppose you ask, “What should I do with my life?” The same basic thing will happen if you ask, “What should I do today,” but the second question may be easier to answer if you have some answer to the first. What sorts of goals do you propose in answer to the first question, and what sort do you actually end up pursuing?

Note that there are constraints on the goals that you can propose. In the first place, you have to be able to describe the goal with the concepts you currently have: you cannot propose to seek a goal that you cannot describe. Second, the conceptual structure itself may rule out some goals, even if they can be described. For example, the idea of good is part of the structure, and if something is thought to be absolutely bad, the Employee will (generally) not consider proposing this as a goal. Likewise, the Employee may suppose that some things are impossible, and it will generally not propose these as goals.

What happens then is this: the Employee proposes some goal, and the CEO, after consultation with the Vice President, decides to accept or reject it, based on the CEO’s own goal of getting good predictions. This is why the Employee is an Employee: it is not the one ultimately in charge. Likewise, as was said, this is why the Employee seems to be doing something impossible, namely choosing goals. Steven Kaas makes a similar point,

You are not the king of your brain. You are the creepy guy standing next to the king going “a most judicious choice, sire”.

This is not quite the same thing, since in our model you do in fact make real decisions, including decisions about the end to be pursued. Nonetheless, the point about not being the one ultimately in charge is correct. David Hume also says something similar when he says, “Reason is, and ought only to be the slave of the passions, and can never pretend to any other office than to serve and obey them.” Hume’s position is not exactly right, and in fact seems an especially bad way of describing the situation, but the basic point that there is something, other than yourself in the ordinary sense, judging your proposed means and ends and deciding whether to accept them, is one that stands.

Sometimes the CEO will veto a proposal precisely because it very obviously leaves things vague and uncertain, which is contrary to its goal of having good predictions. I once spoke of the example that a person cannot directly choose to “write a paper.” In our present model, the Employee proposes “we’re going to write a paper now,” and the CEO responds, “That’s not a viable plan as it stands: we need more detail.”

While neither the CEO nor the Vice President is a rational being, the Vice President is especially irrational, because of the lack of unity among its goals. Both the CEO and the Employee would like to have a unified plan for one’s whole life: the CEO because this makes for good predictions, and the Employee because this is the way final causes work, because it helps to make sense of one’s life, and because “objectively good” seems to imply something which is at least consistent, which will never prefer A to B, B to C, and C to A. But the lack of unity among the Vice President’s goals means that it will always come to the CEO and object, if the person attempts to coherently pursue any goal. This will happen even if it originally accepts the proposal to seek a particular goal.

Consider this real life example from a relationship between an employer and employee:

 

Employer: Please construct a schedule for paying these bills.

Employee: [Constructs schedule.] Here it is.

Employer: Fine.

[Time passes, and the first bill comes due, according to the schedule.]

Employer: Why do we have to pay this bill now instead of later?

 

In a similar way, this sort of scenario is common in our model:

 

Vice President: Being fat makes us look bad. We need to stop being fat.

CEO: Ok, fine. Employee, please formulate a plan to stop us from being fat.

Employee: [Formulates a diet.] Here it is.

[Time passes, and the plan requires skipping a meal.]

Vice President: What is this crazy plan of not eating!?!

CEO: Fine, cancel the plan for now and we’ll get back to it tomorrow.

 

In the real life example, the behavior of the employer is frustrating and irritating to the employee because there is literally nothing they could have proposed that the employer would have found acceptable. In the same way, this sort of scenario in our model is frustrating to the Employee, the conscious person, because there is no consistent plan they could have proposed that would have been acceptable to the Vice President: either they would have objected to being fat, or they would have objected to not eating.

In later posts, we will fill in some details and continue to show how this model explains various aspects of human psychology. We will also answer various objections.

Necessity, Possibility, and Impossibility

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I spoke here about various kinds of necessity, but did not explain the nature of necessity in general. And in the recent post on Hume’s idea of causality, it was not necessary to explain the nature of necessity, because the actual idea of causality does not include necessity. Thus for example a ball can break a window even if it would have been possible for someone to catch the ball, but the person did not do so.

Sometimes it is asked whether necessity implies possibility: if it is necessary that Tuesday follow Monday, it is possible for Tuesday to follow Monday? I am inclined (and I think most are inclined) to say yes, on the grounds that to say that something is not possible is normally understood to imply that the thing is impossible; thus if it is not possible for Tuesday to follow Monday, it is impossible. But this is largely a verbal question: regardless of how we answer this, the real point is that the necessary is the same kind of thing as the possible, except that possibilities are many while the necessary is one. And likewise, a count of zero for the same things implies impossibility. Thus there is something that we are counting: if we find none of them, we speak of an impossibility. If we find only one, we speak of one necessity. And if we find many, we speak of many possibilities.

What are we counting here? Let’s take an example. Horses can be white, or red, or brown, among other possibilities. So there are many possible colors for a horse. And on the other hand snow is always white (or so let us pretend.) So there is only one possible color for snow, and so snow is “necessarily” white. Meanwhile, air is always colorless (or so let us pretend.) So it is impossible for air to have a color. Based on this example, we propose that what we are counting is the number of forms that are suitable for a given matter. Someone might object that if we analyze the word “suitable” here it might involve some sort of circularity. This may well be the case; this is a common occurrence, as with desire and the good, and with virtue and happiness. Nonetheless, I think we will find it worthwhile to work with this definition, just as in those earlier cases.

 

Miracles and Anomalies: Or, Your Religion is False

entirelyuseless Metaphysics, Probability, Religion, Science, Uncategorized , , , , , , , , , , , , , , ,

In 2011 there was an apparent observation of neutrinos traveling faster than light. Wikipedia says of this, “Even before the mistake was discovered, the result was considered anomalous because speeds higher than that of light in a vacuum are generally thought to violate special relativity, a cornerstone of the modern understanding of physics for over a century.” In other words, most scientists did not take the result very seriously, even before any specific explanation was found. As I stated here, it is possible to push unreasonably far in this direction, in such a way that one will be reluctant to ever modify one’s current theories. But there is also something reasonable about this attitude.

Alexander Pruss explains why scientists tend to be skeptical of such anomalous results in this post on Bayesianism and anomaly:

One part of the problem of anomaly is this. If a well-established scientific theory seems to predict something contrary to what we observe, we tend to stick to the theory, with barely a change in credence, while being dubious of the auxiliary hypotheses. What, if anything, justifies this procedure?

Here’s my setup. We have a well-established scientific theory T and (conjoined) auxiliary hypotheses A, and T together with A uncontroversially entails the denial of some piece of observational evidence E which we uncontroversially have (“the anomaly”). The auxiliary hypotheses will typically include claims about the experimental setup, the calibration of equipment, the lack of further causal influences, mathematical claims about the derivation of not-E from T and the above, and maybe some final catch-all thesis like the material conditional that if T and all the other auxiliary hypotheses obtain, then E does not obtain.

For simplicity I will suppose that A and T are independent, though of course that simplifying assumption is rarely true.

…

Here’s a quick and intuitive thought. There is a region of probability space where the conjunction of T and A is false. That area is divided into three sub-regions:

  1. T is true and A is false
  2. T is false and A is true
  3. both are false.

The initial probabilities of the three regions are, respectively, 0.0999, 0.0009999 and 0.0001. We know we are in one of these three regions, and that’s all we now know. Most likely we are in the first one, and the probability that we are in that one given that we are in one of the three is around 0.99. So our credence in T has gone down from three nines (0.999) to two nines (0.99), but it’s still high, so we get to hold on to T.

Still, this answer isn’t optimistic. A move from 0.999 to 0.99 is actually an enormous decrease in confidence.

“This answer isn’t optimistic,” because in the case of the neutrinos, this analysis would imply that scientists should have instantly become ten times more willing to consider the possibility that the theory of special relativity is false. This is surely not what happened.

Pruss therefore presents an alternative calculation:

But there is a much more optimistic thought. Note that the above wasn’t a real Bayesian calculation, just a rough informal intuition. The tip-off is that I said nothing about the conditional probabilities of E on the relevant hypotheses, i.e., the “likelihoods”.

Now setup ensures:

  1. P(E|A ∧ T)=0.

What can we say about the other relevant likelihoods? Well, if some auxiliary hypothesis is false, then E is up for grabs. So, conservatively:

  1. P(E|∼A ∧ T)=0.5
  2. P(E|∼A ∧ ∼T)=0.5

But here is something that I think is really, really interesting. I think that in typical cases where T is a well-established scientific theory and A ∧ T entails the negation of E, the probability P(E|A ∧ ∼T) is still low.

The reason is that all the evidence that we have gathered for T even better confirms the hypothesis that T holds to a high degree of approximation in most cases. Thus, even if T is false, the typical predictions of T, assuming they have conservative error bounds, are likely to still be true. Newtonian physics is false, but even conditionally on its being false we take individual predictions of Newtonian physics to have a high probability. Thus, conservatively:

  1. P(E|A ∧ ∼T)=0.1

Very well, let’s put all our assumptions together, including the ones about A and T being independent and the values of P(A) and P(T). Here’s what we get:

  1. P(E|T)=P(E|A ∧ T)P(A|T)+P(E|∼A ∧ T)P(∼A|T)=0.05
  2. P(E|∼T)=P(E|A ∧ ∼T)P(A|∼T)+P(E|∼A ∧ ∼T)P(∼A|∼T) = 0.14.

Plugging this into Bayes’ theorem, we get P(T|E)=0.997. So our credence has crept down, but only a little: from 0.999 to 0.997. This is much more optimistic (and conservative) than the big move from 0.999 to 0.99 that the intuitive calculation predicted.

So, if I am right, at least one of the reasons why anomalies don’t do much damage to scientific theories is that when the scientific theory T is well-confirmed, the anomaly is not only surprising on the theory, but it is surprising on the denial of the theory—because the background includes the data that makes T “well-confirmed” and would make E surprising even if we knew that T was false.

To make the point without the mathematics (which in any case is only used to illustrate the point, since Pruss is choosing the specific values himself), if you have a theory which would make the anomaly probable, that theory would be strongly supported by the anomaly. But we already know that theories like that are false, because otherwise the anomaly would not be an anomaly. It would be normal and common. Thus all of the actually plausible theories still make the anomaly an improbable observation, and therefore these theories are only weakly supported by the observation of the anomaly. The result is that the new observation makes at most a minor difference to your previous opinion.

We can apply this analysis to the discussion of miracles. David Hume, in his discussion of miracles, seems to desire a conclusive proof against them which is unobtainable, and in this respect he is mistaken. But near the end of his discussion, he brings up the specific topic of religion and says that his argument applies to it in a special way:

Upon the whole, then, it appears, that no testimony for any kind of miracle has ever amounted to a probability, much less to a proof; and that, even supposing it amounted to a proof, it would be opposed by another proof; derived from the very nature of the fact, which it would endeavour to establish. It is experience only, which gives authority to human testimony; and it is the same experience, which assures us of the laws of nature. When, therefore, these two kinds of experience are contrary, we have nothing to do but subtract the one from the other, and embrace an opinion, either on one side or the other, with that assurance which arises from the remainder. But according to the principle here explained, this subtraction, with regard to all popular religions, amounts to an entire annihilation; and therefore we may establish it as a maxim, that no human testimony can have such force as to prove a miracle, and make it a just foundation for any such system of religion.

The idea seems to be something like this: contrary systems of religion put forth miracles in their support, so the supporting evidence for one religion is more or less balanced by the supporting evidence for the other. Likewise, the evidence is weakened even in itself by people’s propensity to lies and delusion in such matters (some of this discussion was quoted in the earlier post on Hume and miracles). But in addition to the fairly balanced evidence we have experience basically supporting the general idea that the miracles do not happen. This is not outweighed by anything in particular, and so it is the only thing that remains after the other evidence balances itself out of the equation. Hume goes on:

I beg the limitations here made may be remarked, when I say, that a miracle can never be proved, so as to be the foundation of a system of religion. For I own, that otherwise, there may possibly be miracles, or violations of the usual course of nature, of such a kind as to admit of proof from human testimony; though, perhaps, it will be impossible to find any such in all the records of history. Thus, suppose, all authors, in all languages, agree, that, from the first of January, 1600, there was a total darkness over the whole earth for eight days: suppose that the tradition of this extraordinary event is still strong and lively among the people: that all travellers, who return from foreign countries, bring us accounts of the same tradition, without the least variation or contradiction: it is evident, that our present philosophers, instead of doubting the fact, ought to receive it as certain, and ought to search for the causes whence it might be derived. The decay, corruption, and dissolution of nature, is an event rendered probable by so many analogies, that any phenomenon, which seems to have a tendency towards that catastrophe, comes within the reach of human testimony, if that testimony be very extensive and uniform.

But suppose, that all the historians who treat of England, should agree, that, on the first of January, 1600, Queen Elizabeth died; that both before and after her death she was seen by her physicians and the whole court, as is usual with persons of her rank; that her successor was acknowledged and proclaimed by the parliament; and that, after being interred a month, she again appeared, resumed the throne, and governed England for three years: I must confess that I should be surprised at the concurrence of so many odd circumstances, but should not have the least inclination to believe so miraculous an event. I should not doubt of her pretended death, and of those other public circumstances that followed it: I should only assert it to have been pretended, and that it neither was, nor possibly could be real. You would in vain object to me the difficulty, and almost impossibility of deceiving the world in an affair of such consequence; the wisdom and solid judgment of that renowned queen; with the little or no advantage which she could reap from so poor an artifice: all this might astonish me; but I would still reply, that the knavery and folly of men are such common phenomena, that I should rather believe the most extraordinary events to arise from their concurrence, than admit of so signal a violation of the laws of nature.

But should this miracle be ascribed to any new system of religion; men, in all ages, have been so much imposed on by ridiculous stories of that kind, that this very circumstance would be a full proof of a cheat, and sufficient, with all men of sense, not only to make them reject the fact, but even reject it without farther examination. Though the Being to whom the miracle is ascribed, be, in this case, Almighty, it does not, upon that account, become a whit more probable; since it is impossible for us to know the attributes or actions of such a Being, otherwise than from the experience which we have of his productions, in the usual course of nature. This still reduces us to past observation, and obliges us to compare the instances of the violation of truth in the testimony of men, with those of the violation of the laws of nature by miracles, in order to judge which of them is most likely and probable. As the violations of truth are more common in the testimony concerning religious miracles, than in that concerning any other matter of fact; this must diminish very much the authority of the former testimony, and make us form a general resolution, never to lend any attention to it, with whatever specious pretence it may be covered.

Notice how “unfair” this seems to religion, so to speak. What is the difference between the eight days of darkness, which Hume would accept, under those conditions, and the resurrection of the queen of England, which he would not? Hume’s reaction to the two situations is more consistent than first appears. Hume would accept the historical accounts about England in the same way that he would accept the accounts about the eight days of darkness. The difference is in how he would explain the accounts. He says of the darkness, “It is evident, that our present philosophers, instead of doubting the fact, ought to receive it as certain, and ought to search for the causes whence it might be derived.” Likewise, he would accept the historical accounts as certain insofar as they say the a burial ceremony took place, the queen was absent from public life, and so on. But he would not accept that the queen was dead and came back to life. Why? The “search for the causes” seems to explain this. It is plausible to Hume that causes of eight days of darkness might be found, but not plausible to him that causes of a resurrection might be found. He hints at this in the words, “The decay, corruption, and dissolution of nature, is an event rendered probable by so many analogies,” while in contrast a resurrection would be “so signal a violation of the laws of nature.”

It is clear that Hume excludes certain miracles, such as resurrection, from the possibility of being established by the evidence of testimony. But he makes the additional point that even if he did not exclude them, he would not find it reasonable to establish a “system of religion” on such testimony, given that “violations of truth are more common in the testimony concerning religious miracles, than in that concerning any other matter of fact.”

It is hard to argue with the claim that “violations of truth” are especially common in testimony about miracles. But does any of this justify Hume’s negative attitude to miracles as establishing “systems of religion,” or is this all just prejudice?  There might well be a good deal of prejudice involved here in his opinions. Nonetheless, Alexander Pruss’s discussion of anomaly allows one to formalize Hume’s idea here as actual insight as well.

One way to look at truth in religion is to look at it as a way of life or as membership in a community. And in this way, asking whether miracles can establish a system of religion is just asking whether a person can be moved to a way of life or to join a community through such things. And clearly this is possible, and often happens. But another way to consider truth in religion is to look at a doctrinal system as a set of claims about how the world is. Looked at in this way, we should look at a doctrinal system as presenting a proposed larger context of our place in the world, one that we would be unaware of without the religion. This implies that one should have a prior probability (namely prior to consideration of arguments in its favor) strongly against the system considered as such, for reasons very much like the reasons we should have a prior probability strongly against Ron Conte’s predictions.

We can thus apply Alexander Pruss’s framework. Let us take Mormonism as the “system of religion” in question. Then taken as a set of claims about the world, our initial probability would be that it is very unlikely that the world is set up this way. Then let us take a purported miracle establishing this system: Joseph Smith finds his golden plates. In principle, if this cashed out in a certain way, it could actually establish his system. But it doesn’t cash out that way. We know very little about the plates, the circumstances of their discovery (if there was any), and their actual content. Instead, what we are left with is an anomaly: something unusual happened, and it might be able to be described as “finding golden plates,” but that’s pretty much all we know.

Then we have the theory, T, which has a high prior probability: Mormonism is almost certainly false. We have the observation : Joseph Smith discovered his golden plates (in one sense or another.) And we have the auxiliary hypotheses which imply that he could not have discovered the plates if Mormonism is false. The Bayesian updates in Pruss’s scheme imply that our conclusion is this: Mormonism is almost certainly false, and there is almost certainly an error in the auxiliary hypotheses that imply he could not have discovered them if it were false.

Thus Hume’s attitude is roughly justified: he should not change his opinion about religious systems in any significant way based on testimony about miracles.

To make you feel better, this does not prove that your religion is false. It just nearly proves that. In particular, this does not take into an account an update based on the fact that “many people accept this set of claims.” This is a different fact, and it is not an anomaly. If you update on this fact and end up with a non-trivial probability that your set of claims is true, testimony about miracles might well strengthen this into conviction.

I will respond to one particular objection, however. Some will take this argument to be stubborn and wicked, because it seems to imply that people shouldn’t be “convinced even if someone rises from the dead.” And this does in fact follow, more or less. An anomalous occurrence in most cases will have a perfectly ordinary explanation in terms of things that are already a part of our ordinary understanding of the world, without having to add some larger context. For example, suppose you heard your fan (as a piece of furniture, not as a person) talking to you. You might suppose that you were hallucinating. But suppose it turns out that you are definitely not hallucinating. Should you conclude that there is some special source from outside the normal world that is communicating with you? No: the fan scenario can happen, and it turns out to have a perfectly everyday explanation. We might agree with Hume that it would be much more implausible that a resurrection would have an everyday explanation. Nonetheless, even if we end up concluding to the existence of some larger context, and that the miracle has no such everyday explanation, there is no good reason for it to be such and such a specific system of doctrine. Consider again Ron Conte’s predictions for the future. Most likely the things that happen between now and 2040, and even the things that happen in the 2400s, are likely to be perfectly ordinary (although the things in the 2400s might differ from current events in fairly radical ways). But even if they are not, and even if apocalyptic, miraculous occurrences are common in those days, this does not raise the probability of Conte’s specific predictions above any trivial level. In the same way, the anomalous occurrences involved in the accounts of miracles will not lend any significant probability to a religious system.

The objection here is that this seems unfair to God, so to speak. What if God wanted to reveal something to the world? What could he do, besides work miracles? I won’t propose a specific answer to this, because I am not God. But I will illustrate the situation with a little story to show that there is nothing unfair to God about it.

Suppose human beings created an artificial intelligence and raised it in a simulated environment. Wanting things to work themselves out “naturally,” so to speak, because it would be less work, and because it would probably be necessary to the learning process, they institute “natural laws” in the simulated world which are followed in an exceptionless way. Once the AI is “grown up”, so to speak, they decide to start communicating with it. In the AI’s world, this will surely show up as some kind of miracle: something will happen that was utterly unpredictable to it, and which is completely inconsistent with the natural laws as it knew them.

Will the AI be forced by the reasoning of this post to ignore the communication? Well, that depends on what exactly occurs and how. At the end of his post, Pruss discusses situations where anomalous occurrences should change your mind:

Note that this argument works less well if the anomalous case is significantly different from the cases that went into the confirmation of T. In such a case, there might be much less reason to think E won’t occur if T is false. And that means that anomalies are more powerful as evidence against a theory the more distant they are from the situations we explored before when we were confirming T. This, I think, matches our intuitions: We would put almost no weight in someone finding an anomaly in the course of an undergraduate physics lab—not just because an undergraduate student is likely doing it (it could be the professor testing the equipment, though), but because this is ground well-gone over, where we expect the theory’s predictions to hold even if the theory is false. But if new observations of the center of our galaxy don’t fit our theory, that is much more compelling—in a regime so different from many of our previous observations, we might well expect that things would be different if our theory were false.

And this helps with the second half of the problem of anomaly: How do we keep from holding on to T too long in the light of contrary evidence, how do we allow anomalies to have a rightful place in undermining theories? The answer is: To undermine a theory effectively, we need anomalies that occur in situations significantly different from those that have already been explored.

If the AI finds itself in an entirely new situation, e.g. rather than hearing an obscure voice from a fan, it is consistently able to talk to the newly discovered occupant of the world on a regular basis, it will have no trouble realizing that its situation has changed, and no difficulty concluding that it is receiving communication from its author. This does, sort of, give one particular method that could be used to communicate a revelation. But there might well be many others.

Our objector will continue. This is still not fair. Now you are saying that God could give a revelation but that if he did, the world would be very different from the actual world. But what if he wanted to give a revelation in the actual world, without it being any different from the way it is? How could he convince you in that case?

Let me respond with an analogy. What if the sky were actually red like the sky of Mars, but looked blue like it is? What would convince you that it was red? The fact that there is no way to convince you that it is red in our actual situation means you are unfairly prejudiced against the redness of the sky.

In other words, indeed, I am unwilling to be convinced that the sky is red except in situations where it is actually red, and those situations are quite different from our actual situation. And indeed, I am unwilling to be convinced of a revelation except in situations where there is actually a revelation, and those are quite different from our actual situation.

Common Sense and Culture

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If we compare what I said about common sense to the letter of St. Augustine on the errors of the Donatists, quoted here, it seems that St. Augustine takes his belief in Christianity to be a matter of accepting common sense:

For they prefer to the testimonies of Holy Writ their own contentions, because, in the case of Cæcilianus, formerly a bishop of the Church of Carthage, against whom they brought charges which they were and are unable to substantiate, they separated themselves from the Catholic Church—that is, from the unity of all nations. Although, even if the charges had been true which were brought by them against Cæcilianus, and could at length be proved to us, yet, though we might pronounce an anathema upon him even in the grave, we are still bound not for the sake of any man to leave the Church, which rests for its foundation on divine witness, and is not the figment of litigious opinions, seeing that it is better to trust in the Lord than to put confidence in man. For we cannot allow that if Cæcilianus had erred,— a supposition which I make without prejudice to his integrity—Christ should therefore have forfeited His inheritance. It is easy for a man to believe of his fellow-men either what is true or what is false; but it marks abandoned impudence to desire to condemn the communion of the whole world on account of charges alleged against a man, of which you cannot establish the truth in the face of the world.

It is true that St. Augustine talks about “divine witness” and so on here, but it is also easy to see that a significant source of his confidence is existing widespread religious agreement. It is foolish to abandon “the unity of all nations,” and impudent to “condemn the communion of the whole world.” And the problem with “charges alleged against a man, of which you cannot establish the truth in the face of the world,” is that if you disagree with the common consent of mankind, you should first attempt to convince others before putting forward your personal ideas as absolute truth.

Is common sense a real reason for St. Augustine’s religious position, or he is merely attempting to justify himself? Consider his famous rebuke of those who attack science in the name of religion:

Usually, even a non-Christian knows something about the earth, the heavens, and the other elements of this world, about the motion and orbit of the stars and even their size and relative positions, about the predictable eclipses of the sun and moon, the cycles of the years and the seasons, about the kinds of animals, shrubs, stones, and so forth, and this knowledge he holds to as being certain from reason and experience. Now, it is a disgraceful and dangerous thing for an infidel to hear a Christian, presumably giving the meaning of Holy Scripture, talking non-sense on these topics; and we should take all means to prevent such an embarrassing situation, in which people show up vast ignorance in a Christian and laugh it to scorn. The shame is not so much that an ignorant individual is derided, but that people outside the household of the faith think our sacred writers held such opinions, and, to the great loss of those for whose salvation we toil, the writers of our Scripture are criticized and rejected as unlearned men. If they find a Christian mistaken in a field which they themselves know well and hear him maintaining his foolish opinions about our books, how are they going to believe those books in matters concerning the resurrection of the dead, the hope of eternal life, and the kingdom of heaven, when they think their pages are full of falsehoods on facts which they themselves have learnt from experience and the light of reason? Reckless and incompetent expounders of holy Scripture bring untold trouble and sorrow on their wiser brethren when they are caught in one of their mischievous false opinions and are taken to task by those who are not bound by the authority of our sacred books. For then, to defend their utterly foolish and obviously untrue statements, they will try to call upon Holy Scripture for proof and even recite from memory many passages which they think support their position, although “they understand neither what they say nor the things about which they make assertion.”

St. Augustine in fact seems to be giving priority to common sense over religion here. If your religion contradicts common sense, your religion is wrong and common sense is right. This suggests that his argument for his religion from common sense is an honest one; it might even be his strongest reason for his belief.

As I said in the earlier post, the argument for religion from the consent of humanity had problems even at the time, and as things stand, it has no real relevance. There is no religious doctrine, let alone any religion, that one could reasonably say is accepted by even a majority of humanity, let alone by all. At any rate, this is the case unless one makes one’s doctrine far vaguer than would be permitted by any religion.

I concluded above that St. Augustine’s defense of common sense is likely an honest one. But note that this was not necessary: it would be perfectly possible for someone to defend common sense in order to justify themselves, without actually caring about the truth of common sense. In fact, consider what I said here about Scott Sumner and James Larson. Larson’s claim to accept realism is basically not an honest one. I do not mean that he does not believe it, but that its truth is irrelevant to him. What matters to him is that he can seemingly justify himself in maintaining his religious position in the face of all opposition.

Consider the cynical position of Francis Bacon about people relative to truth, discussed here. According to Bacon, no one is interested in truth in itself, but only as a means to other things. While the cynical position overall is incorrect, there is a lot of truth in it. Consequently, it will not be uncommon for someone to defend common sense, not so much because of its truth, but as part of a larger project of defending their culture. Culture is bound up with claims about the world, and defending culture therefore involves defending claims about the world. And if everyone accepts something, presumably everyone in your culture accepts it. One sign of this, of course, would be if someone passes freely back and forth between putting forth things that everyone accepts, and things that everyone in their culture accepts, as though these were equivalent.

Likewise, someone can attack common sense, not for the purpose of truth, but in order to engage in a kind of culture war. Consider the recent comments by “werzekeugjj” on the last post. There is no option here but to explain these comments with the methods of Ezekiel Bulver. For they cannot possibly represent opinions about the world at all, let alone opinions that were arrived at by honest means. Werzekeugjj, for example, responds to the question, “Do people sometimes write comments?” with “No.” As I pointed out there, if they do not, then he did not compose those comments, and there is nothing to reply to. As Aristotle puts it,

We can, however, demonstrate negatively even that this view is impossible, if our opponent will only say something; and if he says nothing, it is absurd to seek to give an account of our views to one who cannot give an account of anything, in so far as he cannot do so. For such a man, as such, is from the start no better than a vegetable.

Nor is it possible to apply a principle of charity here and say that Werzekeugjj intends to say that their claims are true in some complicated metaphysical sense. This does apply to the position of the blogger from Atheism and the City, discussed in that post. He presumably does not intend to reject common sense. I simply point out in my response that common sense is enough to draw the conclusions about causality that matter. The point is that this cannot apply to Werzekeugjj’s expressed position, because I spoke expressly of things in the everyday way, and the response was that the everyday claims themselves are false.

Of course, no one actually thinks that the everyday claims are false, including Werzekeugjj. What was the purpose of composing these comments, then?

We can gather a clue from this comment:

“in such a block unniverse there is no time flow
so your point on finalism or causality is moot
same with God
they don’t exist

The body of the post does not mention God, and God is not the topic. Why then does Werzekeugjj bring up God here? The most likely motivation is the kind of culture war motivation discussed here. Werzekeugjj associated talk of causality and reasons with talk of God, and intends to attack a culture that speaks this way with whatever it takes, including a full on rejection of common sense. Science has shown that your common sense views of the world are entirely false, Werzekeugjj says, and therefore you might as well abandon the rest of your culture (including its talk of God) along with the rest of your views.

Supposedly describing their intentions, Werzekeugjj says,

i’m not trying to understand the world or to change your mind but i’m trying to state what is true
and i’m puzzled by how you think there is no problem with arguments like these

This is false, precisely as a description of their personal motives. No one who says that balls never break windows and that they did not write their comments (in the very comments themselves) can pretend to be “trying to state what is true.” Sorry, but that is not your intention. More reasonably, we can suppose that Werzekeugjj sees my post as part of a project of defending a certain culture, and they intend to attack that culture.

But that is an inaccurate understanding of the post. I defend common sense because it is right, not because it is a part of any particular culture. As Bryan Caplan puts it, “Common sense is the foundation of all reasoning.  If you want to reject a common-sense claim, you’d better do it in the name of an even stronger common-sense claim.”