# Structure of Explanation

When we explain a thing, we give a cause; we assign the thing an origin that explains it.

We can go into a little more detail here. When we ask “why” something is the case, there is always an implication of possible alternatives. At the very least, the question implies, “Why is this the case rather than not being the case?” Thus “being the case” and “not being the case” are two possible alternatives.

The alternatives can be seen as possibilities in the sense explained in an earlier post. There may or may not be any actual matter involved, but again, the idea is that reality (or more specifically some part of reality) seems like something that would be open to being formed in one way or another, and we are asking why it is formed in one particular way rather than the other way. “Why is it raining?” In principle, the sky is open to being clear, or being filled with clouds and a thunderstorm, and to many other possibilities.

A successful explanation will be a complete explanation when it says “once you take the origin into account, the apparent alternatives were only apparent, and not really possible.” It will be a partial explanation when it says, “once you take the origin into account, the other alternatives were less sensible (i.e. made less sense as possibilities) than the actual thing.”

Let’s consider some examples in the form of “why” questions and answers.

Q1. Why do rocks fall? (e.g. instead of the alternatives of hovering in the air, going upwards, or anything else.)

A1. Gravity pulls things downwards, and rocks are heavier than air.

The answer gives an efficient cause, and once this cause is taken into account, it can be seen that hovering in the air or going upwards were not possibilities relative to that cause.

Obviously there is not meant to be a deep explanation here; the point here is to discuss the structure of explanation. The given answer is in fact basically Newton’s answer (although he provided more mathematical detail), while with general relativity Einstein provided a better explanation.

The explanation is incomplete in several ways. It is not a first cause; someone can now ask, “Why does gravity pull things downwards, instead of upwards or to the side?” Similarly, while it is in fact the cause of falling rocks, someone can still ask, “Why didn’t anything else prevent gravity from making the rocks fall?” This is a different question, and would require a different answer, but it seems to reopen the possibility of the rocks hovering or moving upwards, from a more general point of view. David Hume was in part appealing to the possibility of such additional questions when he said that we can see no necessary connection between cause and effect.

Q2. Why is 7 prime? (i.e. instead of the alternative of not being prime.)

A2. 7/2 = 3.5, so 7 is not divisible by 2. 7/3 = 2.333…, so 7 is not divisible by 3. In a similar way, it is not divisible by 4, 5, or 6. Thus in general it is not divisible by any number except 1 and itself, which is what it means to be prime.

If we assumed that the questioner did not know what being prime means, we could have given a purely formal response simply by noting that it is not divisible by numbers between 1 and itself, and explaining that this is what it is to be prime. As it is, the response gives a sufficient material disposition. Relative to this explanation, “not being prime,” was never a real possibility for 7 in the first place. The explanation is complete in that it completely excludes the apparent alternative.

Q3. Why did Peter go to the store? (e.g. instead of going to the park or the museum, or instead of staying home.)

A3. He went to the store in order to buy groceries.

The answer gives a final cause. In view of this cause the alternatives were merely apparent. Going to the park or the museum, or even staying home, were not possible since there were no groceries there.

As in the case of the rock, the explanation is partial in several ways. Someone can still ask, “Why did he want groceries?” And again someone can ask why he didn’t go to some other store, or why something didn’t hinder him, and so on. Such questions seem to reopen various possibilities, and thus the explanation is not an ultimately complete one.

Suppose, however, that someone brings up the possibility that instead of going to the store, he could have gone to his neighbor and offered money for groceries in his neighbor’s refrigerator. This possibility is not excluded simply by the purpose of buying groceries. Nonetheless, the possibility seems less sensible than getting them from the store, for multiple reasons. Again, the implication is that our explanation is only partial: it does not completely exclude alternatives, but it makes them less sensible.

Let’s consider a weirder question: Why is there something rather than nothing?

Now the alternatives are explicit, namely there being something, and there being nothing.

It can be seen that in one sense, as I said in the linked post, the question cannot have an answer, since there cannot be a cause or origin for “there is something” which would itself not be something. Nonetheless, if we consider the idea of possible alternatives, it is possible to see that the question does not need an answer; one of the alternatives was only an apparent alternative all along.

In other words, the sky can be open to being clear or cloudy. But there cannot be something which is open both to “there is something” and “there is nothing”, since any possibility of that kind would be “something which is open…”, which would already be something rather than nothing. The “nothing” alternative was merely apparent. Nothing was ever open to there being nothing.

Let’s consider another weird question. Suppose we throw a ball, and in the middle of the path we ask, Why is the ball in the middle of the path instead of at the end of the path?

We could respond in terms of a sufficient material disposition: it is in the middle of the path because you are asking your question at the middle, instead of waiting until the end.

Suppose the questioner responds: Look, I asked my question at the middle of the path. But that was just chance. I could have asked at any moment, including at the end. So I want to know why it was in the middle without considering when I am asking the question.

If we look at the question in this way, it can be seen in one way that no cause or origin can be given. Asked in this way, being at the end cannot be excluded, since they could have asked their question at the end. But like the question about something rather than nothing, the question does not need an answer. In this case, this is not because the alternatives were merely apparent in the sense that one was possible and the other not. But they were merely apparent in the sense that they were not alternatives. The ball goes both goes through the middle, and reaches the end. With the stipulation that we not consider the time of the question, the two possibilities are not mutually exclusive.

The above considerations about the nature of “explanation” lead to various conclusions, but also to various new questions. For example, one commenter suggested that “explanation” is merely subjective. Now as I said there, all experience is subjective experience (what would “objective experience” even mean, except that someone truly had a subjective experience?), including the experience of having an explanation. Nonetheless, the thing experienced is not subjective: the origins that we call explanations objectively exclude the apparent possibilities, or objectively make them less intelligible. The explanation of explanation here, however, provides an answer to what was perhaps the implicit question. Namely, why are we so interested in explanations in the first place, so that the experience of understanding something becomes a particularly special type of experience? Why, as Aristotle puts it, do “all men desire to know,” and why is that desire particularly satisfied by explanations?

In one sense it is sufficient simply to say that understanding is good in itself. Nonetheless, there is something particular about the structure of a human being that makes knowledge good for us, and which makes explanation a particularly desirable form of knowledge. In my employer and employee model of human psychology, I said that “the whole company is functioning well overall when the CEO’s goal of accurate prediction is regularly being achieved.” This very obviously requires knowledge, and explanation is especially beneficial because it excludes alternatives, which reduces uncertainty and therefore tends to make prediction more accurate.

However, my account also raises new questions. If explanation eliminates alternatives, what would happen if everything was explained? We could respond that “explaining everything” is not possible in the first place, but this is probably an inadequate response, because (from the linked argument) we only know that we cannot explain everything all at once, the way the person in the room cannot draw everything at once; we do not know that there is any particular thing that cannot be explained, just as there is no particular aspect of the room that cannot be drawn. So there can still be a question about what would happen if every particular thing in fact has an explanation, even if we cannot know all the explanations at once. In particular, since explanation eliminates alternatives, does the existence of explanations imply that there are not really any alternatives? This would suggest something like Leibniz’s argument that the actual world is the best possible world. It is easy to see that such an idea implies that there was only one “possibility” in the first place: Leibniz’s “best possible world” would be rather “the only possible world,” since the apparent alternatives, given that they would have been worse, were not real alternatives in the first place.

On the other hand, if we suppose that this is not the case, and there are ultimately many possibilities, does this imply the existence of “brute facts,” things that could have been otherwise, but which simply have no explanation? Or at least things that have no complete explanation?

Let the reader understand. I have already implicitly answered these questions. However, I will not link here to the implicit answers because if one finds it unclear when and where this was done, one would probably also find those answers unclear and inconclusive. Of course it is also possible that the reader does see when this was done, but still believes those responses inadequate. In any case, it is possible to provide the answers in a form which is much clearer and more conclusive, but this will likely not be a short or simple project.

# Violations of Bell’s Inequality: Drawing Conclusions

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.

# Spooky Action at a Distance

Albert Einstein objected to the usual interpretations of quantum mechanics because they seemed to him to imply “spooky action at a distance,” a phrase taken from a letter from Einstein to Max Born in 1947 (page 155 in this book):

I cannot make a case for my attitude in physics which you would consider at all reasonable. I admit, of course, that there is a considerable amount of validity in the statistical approach which you were the first to recognize clearly as necessary given the framework of the existing formalism. I cannot seriously believe in it because the theory cannot be reconciled with the idea that physics should represent a reality in time and space, free from spooky actions at a distance. I am, however, not yet firmly convinced that it can really be achieved with a continuous field theory, although I have discovered a possible way of doing this which so far seems quite reasonable. The calculation difficulties are so great that I will be biting the dust long before I myself can be fully convinced of it. But I am quite convinced that someone will eventually come up with a theory whose objects, connected by laws, are not probabilities but considered facts, as used to be taken for granted until quite recently. I cannot, however, base this conviction on logical reasons, but can only produce my little finger as witness, that is, I offer no authority which would be able to command any kind of respect outside of my own hand.

Einstein has two objections: the theory seems to be indeterministic, and it also seems to imply action at a distance. He finds both of these implausible. He thinks physics should be deterministic, “as used to be taken for granted until quite recently,” and that all interactions should be local: things directly affect only things which are close by, and affect distant things only indirectly.

In many ways, things do not appear to have gone well for Einstein’s intuitions. John Bell constructed a mathematical argument, now known as Bell’s Theorem, that the predictions of quantum mechanics cannot be reproduced by the kind of theory desired by Einstein. Bell summarizes his point:

The paradox of Einstein, Podolsky and Rosen was advanced as an argument that quantum mechanics could not be a complete theory but should be supplemented by additional variables. These additional variables were to restore to the theory causality and locality. In this note that idea will be formulated mathematically and shown to be incompatible with the statistical predictions of quantum mechanics. It is the requirement of locality, or more precisely that the result of a measurement on one system be unaffected by operations on a distant system with which it has interacted in the past, that creates the essential difficulty. There have been attempts to show that even without such a separability or locality requirement no “hidden variable” interpretation of quantum mechanics is possible. These attempts have been examined elsewhere and found wanting. 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.

“Causality and locality” in this description are exactly the two points where Einstein objected in the quoted letter: causality, as understood here, implies determinism, and locality implies no spooky action at a distance. Given this result, Einstein might have hoped that the predictions of quantum mechanics would turn out to fail, so that he could still have his desired physics. This did not happen. On the contrary, these predictions (precisely those inconsistent with such theories) have been verified time and time again.

Rather than putting the reader through Bell’s math and physics, we will explain his result with an analogy by Mark Alford. Alford makes this comparison:

Imagine that someone has told us that twins have special powers, including the ability to communicate with each other using telepathic influences that are “superluminal” (faster than light). We decide to test this by collecting many pairs of twins, separating each pair, and asking each twin one question to see if their answers agree.

To make things simple we will only have three possible questions, and they will be Yes/No questions. We will tell the twins in advance what the questions are.

The procedure is as follows.

1. A new pair of twins is brought in and told what the three possible questions are.
2. The twins travel far apart in space to separate questioning locations.
3. At each location there is a questioner who selects one of the three questions at random, and poses that question to the twin in front of her.
4. Spacelike separation. When the question is chosen and asked at one location, there is not enough time for any influence traveling at the speed of light to get from there to the other location in time to affect either what question is chosen there, or the answer given.

He now supposes the twins give the same responses when they are asked the same question, and discusses this situation:

Now, suppose we perform this experiment and we find same-question agreement: whenever a pair of spacelike-separated twins both happen to get asked the same question, their answers always agree. How could they do this? There are two possible explanations,

1. Each pair of twins uses superluminal telepathic communication to make sure both twins give the same answer.

2. Each pair of twins follows a plan. Before they were separated they agreed in advance what their answers to the three questions would be.

The same-question agreement that we observe does not prove that twins can communicate telepathically faster than light. If we believe that strong locality is a valid principle, then we can resort to the other explanation, that each pair of twins is following a plan. The crucial point is that this requires determinism. If there were any indeterministic evolution while the twins were spacelike separated, strong locality requires that the random component of one twin’s evolution would have to be uncorrelated with the other twin’s evolution. Such uncorrelated indeterminism would cause their recollections of the plan to diverge, and they would not always show same-question agreement.

The results are understandable if the twins agree on the answers Yes-Yes-Yes, or Yes-No-Yes, or any other determinate combination. But they are not understandable if they decide to flip coins if they are asked the second question, for example. If they did this, they would have to disagree 50% of the time on that question, unless one of the coin flips affected the other.

Alford goes on to discuss what happens when the twins are asked different questions:

In the thought experiment as described up to this point we only looked at the recorded answers in cases where each twin in a given pair was asked the same question. There are also recorded data on what happens when the two questioners happen to choose different questions. Bell noticed that this data can be used as a cross-check on our strong-locality-saving idea that the twins are following a pre-agreed plan that determines that their answers will always agree. The cross-check takes the form of an inequality:

Bell inequality for twins:

If a pair of twins is following a plan then, when each twin is asked a different randomly chosen question, their answers will be the same, on average, at least 1/3 of the time.

He derives this value:

For each pair of twins, there are four general types of pre-agreed plan they could adopt when they are arranging how they will both give the same answer to each of the three possible questions.

(a) a plan in which all three answers are Yes;

(b) a plan in which there are two Yes and one No;

(c) a plan in which there are two No and one Yes;

(d) a plan in which all three answers are No.

If, as strong locality and same-question agreement imply, both twins in a given pair follow a shared predefined plan, then when the random questioning leads to each of them being asked a different question from the set of three possible questions, how often will their answers happen to be the same (both Yes or both No)? If the plan is of type (a) or (d), both answers will always be the same. If the plan is of type (b) or (c), both answers will be the same 1/3 of the time. We conclude that no matter what type of plan each pair of twins may follow, the mere fact that they are following a plan implies that, when each of them is asked a different randomly chosen question, they will both give the same answer (which might be Yes or No) at least 1/3 of the time. It is important to appreciate that one needs data from many pairs of twins to see this effect, and that the inequality holds even if each pair of twins freely chooses any plan they like.

The “Bell inequality” is violated if we do the experimental test and the twins end up agreeing, when they are asked different questions, less than 1/3 of the time, despite consistently agreeing when they are asked the same question. If one saw such results in reality, one might be forgiven for concluding that the twins do have superluminal telepathic abilities. Unfortunately for Einstein, this is what we do get, consistently, when we test the analogous quantum mechanical version of the experiment.

# Generalized Kantian Dichotomy

At the end of the last post I suggested that the confusion between the mode of knowledge and the mode of being might be a primary, or rather the primary, cause of philosophical error, with the exception of motivated error.

If we consider the “Kantian” and “anti-Kantian” errors in the last post, we can give a somewhat general account of how this happens. The two errors might appear to be mutually exclusive and exhaustive, but in fact they constitute a false dichotomy. Consider the structure of the disagreement:

A. Common sense takes note of something: in this case, that it is possible to know things. Knowledge is real.

B. The Kantian points out that the mode of knowing and the mode of being are not the same, and concludes that common sense is wrong. Knowledge is apparent, but not real.

C. The anti-Kantian, determined to uphold common sense, applies modus tollens. We know that knowledge is real: so the mode of knowing and the mode of being must be the same.

Each party to the dispute says something true (that knowledge is real, that the mode of being and the mode of knowing are not the same), and something false (that knowledge is not real, that the mode of being and the mode of knowing are the same.)

A vast number of philosophical disputes can be analyzed in a very similar manner. Thus we have the general structure:

A. Common sense points out that some item X is real.

B. The Kantian points out that the mode of knowing and the mode of being are not the same, and concludes that common sense is wrong. X is apparent, but not real.

C. The anti-Kantian, determined to uphold common sense, applies modus tollens. We know that X is real: so the mode of knowing and the mode of being must be the same.

Once again, in this general structure, each party to the dispute would say something true (that X is real, that the mode of knowing and being are not the same), and something false (the denial of one of these two.) As an example, we can apply this structure to our discussion of reductionism and anti-reductionism. The reductionist, in this case, is the Kantian (in our present structure), and the anti-reductionist the anti-Kantian. The very same person might well argue both sides about different things: thus Sean Carroll might be anti-reductionist about fundamental particles and reductionist about humans, while Alexander Pruss is anti-reductionist about humans and reductionist about artifacts. But whether we are discussing fundamental particles, humans, or artifacts, both sides are wrong. Both say something true, but also something false.

Several cautionary notes are needed in this regard.

First, both sides will frequently realize that they are saying something strongly counter-intuitive, and attempt to remedy this by saying something along the lines of “I don’t mean to say the thing that is false.” But that is not the point. I do not say that you intend to say the thing that is false. I say that you give an account which logically implies the thing that is false, and that the only way you can avoid this implication is by rejecting the false dichotomy completely, namely by accepting both the reality of X, and the distinction of the modes of knowing and being. Thus for example Sean Carroll’s does not distinguish his poetic naturalism from eliminativism in terms of what it says to be true, but only in terms of what it says to be useful. But eliminativism says that it is false that there are ships: therefore Carroll’s poetic naturalism also says that it is false that there are ships, whether he intends to say this or not, and whether or not he finds it useful to say that there are.

Second, this outline uses the terminology of “Kantian” and “anti-Kantian,” but in fact the two tend to blur into one another, because the mistakes are very similar: both imply that the unknown and the known, as such, are the same. Thus for example in my post on reductionism I said that there was a Kantian error in the anti-reductionist position: but in the present schema, the error is anti-Kantian. In part, this happened because I did not make these distinctions clearly enough myself in the earlier post. But is it also because the errors themselves uphold very similar contradictions. Thus the anti-reductionist thinks somewhat along these lines:

We know that a human being is one thing. We know it as a unity, and therefore it has a mode of being as a unity. But whenever anyone tries to explain the idea of a human being, they end up saying many things about it. So our explanation of a human being cannot be the true explanation. Since the mode of knowing and the mode of being must be the same, a true explanation of a human being would have to be absolutely one. We have no explanation like that, so it must be that a human being has an essence which is currently hidden from us.

Note that this reasons in an anti-Kantian manner (the mode of being and the mode of knowing must be the same), but the conclusion is effectively Kantian: possible or not, we actually have no knowledge of human beings as they are.

As I said in the post on reductionism, the parties to the dispute will in general say that an account like mine is anti-realist: realism, according to both sides, requires that one accept one side of the dichotomy and reject the other. But I respond that the very dispute between realism and anti-realism can be itself an example of the false dichotomy, as the dispute is often understood. Thus:

A. Common sense notes that the things we normally think and talk about are real, and that the things we normally say about them are true.

B. The Kantian (the anti-realist) points out that the mode of knowing and the mode of being are not the same, and concludes that common sense is wrong. The things we normally talk about appear to be real, but they are not.

C. The anti-Kantian (the realist) applies modus tollens. We know these things are real: so the mode of knowledge and the mode of being must be the same after all.

As usual, both say something true, and both say something false. Consider Scott Sumner, who tends to take an anti-realist position, as for example here:

Even worse, I propose doing so for “postmodern” reasons. I will start by denying the reality of inflation, and then argue for some substitute concepts that are far more useful. First a bit of philosophy. There is a lively debate about whether there is a meaningful distinction between our perception of reality, and actual reality. I had a long debate with a philosopher about whether Newton’s laws of motion were a part of reality, or merely a human construct. I took the latter view, arguing that if humans had never existed then Newton’s laws would have never existed. He argued they are objectively true. I responded that Einstein showed that were false. He responded that they were objectively true in the limiting case. I argued that even that might be changed by future developments in our understanding of reality at the quantum level. He argued that they’d still be objectively approximately true, etc, etc.

On the one hand, a lot of what Scott says here is right. On the other hand, he mistakenly believes that it follows that common sense is mistaken in matters in which it is not, in fact, mistaken. The reasoning is basically the reasoning of the Kantian: one notices that we have a specific mode of knowing which is not the mode of being of things, and concludes that knowledge is impossible, or in Scott’s terminology, “objective truth” does not exist, at least as distinct from personal opinion. He has a more extensive discussion of this here:

I don’t see it as relativism at all. I don’t see it as the world of fuzzy post-modern philosophers attacking the virtuous hard sciences. It’s important not to get confused by semantics, and focus on what’s really at stake. In my view, Rorty’s views are most easily seen by considering his denial of the distinction between objective truth and subjective belief. In order to see why he did this, consider Rorty’s claim that, “That which has no practical implications, has no theoretical implications.” Suppose Rorty’s right, and it’s all just belief that we hold with more or less confidence. What then? In contrast, suppose the distinction between subjective belief and objective fact is true. What then? What are the practical implications of each philosophical view? I believe the most useful way of thinking about this is to view all beliefs as subjective, albeit held with more or less confidence.

Let’s suppose it were true that we could divide up statements about the world into two categories, subjective beliefs and objective facts. Now let’s write down all our statements about the world onto slips of paper. Every single one of them, there must be trillions (even if we ignore the field of math, where an infinite number of statements could be constructed.) Now let’s divide these statements up into two big piles, one set is subjective beliefs, and the other pile contains statements that are objective facts. We build a vast Borgesian library, and put all the subjective beliefs (i.e. Trump is an idiot) into one wing, and all the objective facts (Paris is the capital of France) into the other wing.

Now here’s the question for pragmatists like Rorty and me. Is this a useful distinction to make? If it is useful, how is it useful? Here’s the only useful thing I can imagine resulting from this distinction. If we have a category of objective facts, then we can save time by not questioning these facts as new information arises. They are “off limits”. Since they are objective facts, they can never be refuted. If they could be refuted, then they’d be subjective beliefs, not objective facts.

But I don’t want to do that. I don’t want to consider any beliefs to be completely off limits—not at all open to refutation. That reminds me too much of fundamentalist religion. On the other hand, I do want to distinguish between different kinds of beliefs, in a way that I think is more pragmatic than the subjective/objective distinction. Rather I’d like to assign probability values to each belief, which represent my confidence as to whether or not the belief is true. Then I’d like to devote more of my time to entertaining critiques of highly questionable hypotheses, than I do to less plausible hypotheses.

Again, this makes a great deal of sense. The problem is that Scott thinks that either there is no distinction between the subjective and objective, or we need to be able to make that distinction subjectively. Since the latter seems an evident contradiction, he concludes that there is no distinction between subjective and objective. Later in the post, he puts this in terms of “map and territory”:

The other point of confusion I see is people conflating “the map and the territory”. Then they want to view “objective facts” as aspects of the territory, the underlying reality, not (just) beliefs about the territory. I don’t think that’s very useful, as it seems to me that statements about the world are always models of the world, not the world itself. Again, if it were not true, then theories could never be revised over time. After all, Einstein didn’t revise reality in 1905; he revised our understanding of reality–our model of reality.

“Statements about the world are always models of the world, not the world itself.” Indeed. That is because they are statements, not the things the statements are about. This is correctly to notice that the mode of knowledge is not the mode of being. But it does not follow that there are no objective facts, nor that objective facts are not distinct from opinions. Consider the statement that “dogs are animals.” We can call that statement a “model of the world.” But is not about a model of the world: it is about dogs, which are not our model or even parts of our model, but things moving around outside in the real world. Obviously, we cannot concretely distinguish between “things we think are true” and “things that are actually true,” because it will always be us talking about things that are actually true, but we can make and understand that distinction in the abstract. Scott is right, however, to reject the idea that some ideas are subjective “because they are about the map,” with other statements being objective “because they are about the territory.” In the map / territory terminology, all statements are maps, and all of them are about the territory (including statements about maps, which refer to maps as things that exist, and thus as part of the territory.)

We can see here how Scott Sumner is falling into the Kantian error. But what about the realist position? It does not follow from any of the above that the realist must make any corresponding error. And indeed, in all such dichotomies, there will be a side which is more right than the other: namely, the side that says that common sense is right. And so it is possible, and correct, to say that common sense is right without also accepting the corresponding falsehood (namely that the mode of knowing and the mode of being are the same.) But if we do accept the realist position together with the corresponding falsehood, this can manifest itself in various ways. For example, one might say that one should indeed put some things in the category of “off limits” for discussion: since they are objective facts, they can never be revised. Thus for example James Larson, as in an earlier discussion, tends to identify the rejection of his positions with the rejection of realism. In effect, “My beliefs are objectively true. So people who disagree with my beliefs reject objective truth. And I cannot admit that my beliefs might be false, because that would mean an objective truth could be false at the same time, which is a contradiction.” The problem will not always be manifested in the same way, however, because as we said in the last post, each end of the false dichotomy implies a similar contradiction and cannot be reasoned about coherently.

# Really and Truly True

There are two persons in a room with a table between them. One says, “There is a table on the right.” The other says, “There is a table on the left.”

Which person is right? The obvious answer is that both are right. But suppose they attempt to make this into a metaphysical disagreement.

“Yes, in a relative sense, the table is on the right of one of us and on the left of the other. But really and truly, at a fundamental level, the table is on the right, and not on the left.”

“I agree that there must be a fundamental truth to where the table is. But I think it is really and truly on the left, and not on the right.”

Now both are wrong, because it is impossible for the relationships of “on the right” and “on the left” to exist without correlatives, and the assertion that the table is “really and truly” on the right or on the left means nothing here except that these things do not depend on a relationship to an observer.

Thus both people are right, if they intend their assertions in a common sense way, and both are wrong, if they intend their assertions in the supposed metaphysical way. Could it happen that one is right and the other wrong? Yes, if one intends to speak in the common sense way, and the other in the metaphysical way, but not if they are speaking in the same way.

In the Mathematical Principles of Natural Philosophy, Newton explains his ideas of space and time:

I. Absolute, true, and mathematical time, of itself, and from its own nature flows equably without regard to anything external, and by another name is called duration: relative, apparent, and common time, is some sensible and external (whether accurate or unequable) measure of duration by the means of motion, which is commonly used instead of true time; such as an hour, a day, a month, a year.

II. Absolute space, in its own nature, without regard to anything external, remains always similar and immovable. Relative space is some movable dimension or measure of the absolute spaces; which our senses determine by its position to bodies; and which is vulgarly taken for immovable space; such is the dimension of a subterraneous, an æreal, or celestial space, determined by its position in respect of the earth. Absolute and relative space, are the same in figure and magnitude; but they do not remain always numerically the same. For if the earth, for instance, moves, a space of our air, which relatively and in respect of the earth remains always the same, will at one time be one part of the absolute space into which the air passes; at another time it will be another part of the same, and so, absolutely understood, it will be perpetually mutable.

III. Place is a part of space which a body takes up, and is according to the space, either absolute or relative. I say, a part of space; not the situation, nor the external surface of the body. For the places of equal solids are always equal; but their superfices, by reason of their dissimilar figures, are often unequal. Positions properly have no quantity, nor are they so much the places themselves, as the properties of places. The motion of the whole is the same thing with the sum of the motions of the parts; that is, the translation of the whole, out of its place, is the same thing with the sum of the translations of the parts out of their places; and therefore the place of the whole is the same thing with the sum of the places of the parts, and for that reason, it is internal, and in the whole body.

IV. Absolute motion is the translation of a body from one absolute place into another; and relative motion, the translation from one relative place into another. Thus in a ship under sail, the relative place of a body is that part of the ship which the body possesses; or that part of its cavity which the body fills, and which therefore moves together with the ship: and relative rest is the continuance of the body in the same part of the ship, or of its cavity. But real, absolute rest, is the continuance of the body in the same part of that immovable space, in which the ship itself, its cavity, and all that it contains, is moved. Wherefore, if the earth is really at rest, the body, which relatively rests in the ship, will really and absolutely move with the same velocity which the ship has on the earth. But if the earth also moves, the true and absolute motion of the body will arise, partly from the true motion of the earth, in immovable space; partly from the relative motion of the ship on the earth; and if the body moves also relatively in the ship; its true motion will arise, partly from the true motion of the earth, in immovable space, and partly from the relative motions as well of the ship on the earth, as of the body in the ship; and from these relative motions will arise the relative motion of the body on the earth. As if that part of the earth, where the ship is, was truly moved toward the east, with a velocity of 10010 parts; while the ship itself, with a fresh gale, and full sails, is carried towards the west, with a velocity expressed by 10 of those parts; but a sailor walks in the ship towards the east, with 1 part of the said velocity; then the sailor will be moved truly in immovable space towards the east, with a velocity of 10001 parts, and relatively on the earth towards the west, with a velocity of 9 of those parts.

While the details of Einstein’s theory of relativity may have been contingent, it is not difficult to see that Newton’s theory here is mistaken, and that anyone could have known it at the time. It is mistaken in precisely the way the people described above are mistaken in saying that the table is “really and truly” on the left or on the right.

For example, suppose the world had a beginning in time. Does it make sense to ask whether it could have started at a later time, or at an earlier one? It does not, because “later” and “earlier” are just as relative as “on the left” and “on the right,” and there is nothing besides the world in relation to which the world could have these relations. Could all bodies have been shifted a bit in one direction or another? No. This has no meaning, just as it has no meaning to be on the right without being on the right of something or other.

In an amusing exchange some years ago between Vladimir Nesov and Eliezer Yudkowsky, Nesov says:

Existence is relative: there is a fact of the matter (or rather: procedure to find out) about which things exist where relative to me, for example in the same room, or in the same world, but this concept breaks down when you ask about “absolute” existence. Absolute existence is inconsistent, as everything goes. Relative existence of yourself is a trivial question with a trivial answer.

Yudkowsky responds:

Absolute existence is inconsistent

Wha?

Yudkowsky is taken aback by the seemingly nonchalant affirmation of an apparently abstruse metaphysical claim, which if not nonsensical would appear to be the absurd claim that existence is impossible.

But Nesov is quite right: to exist is to exist in relation to other things. Thus to exist “absolutely” would be like “being absolutely on the right,” which is impossible.

Suppose we confront our original disputants with the fact that right and left are relative terms, and there is no “really true truth” about the relative position of the table. It is both on the right and on the left, relative to the disputants, and apart from these relationships, it is neither.

“Ok,” one responds, “but there is still a deep truth about where the table is: it is here in this room.”

“Actually,” the other answers, “The real truth is that it is in the house.”

Once again, both are right, if these are taken as common sense claims, and both are wrong, if this is intended to be a metaphysical dispute where one would be true, the real truth about where the table is, and the other would be false.

Newton’s idea of absolute space is an extension of this argument: “Ok, then, but there is still a really true truth about where the table is: it is here in absolute space.” But obviously this is just as wrong as all the other attempts to find out where the table “really” is. The basic problem is that “where is this” demands a relative response. It is a question about relationships in the first place. We can see this in fact even in Newton’s account: it is here in absolute space, that is, it is close to certain areas of absolute space and distant from certain other areas of absolute space.

Something similar will be true about existence to the degree that existence is also implicitly relative. “Where is this thing in the nature of things?” also requires a relative response: what relationship does this have to the rest of the order of reality? And in a similar way, questions about what is “really and truly true,” if taken to imply an abstraction from this relative order, will not have any answer. In a previous post, I said something like this in relation to the question, “how many things are here?” Reductionists and anti-reductionists disputing about whether a large object is “really and truly a cloud of particles” or “really and truly a single object,” are in exactly the same position as the disputants about the position of the table: both claims are true, in a common sense way, and both claims are false, if taken in a mutually exclusive metaphysical sense, since speaking of one or many is already to involve the perspective of the knower, in particular as knowing division and its negation.

Of course, an anti-reductionist has some advantage here because they can respond, “Actually, no one in a normal context would ever call a large object a cloud of particles. So it is not common sense at all.” This is true as far as it goes, but it is not really to the point, since no one denies in a common sense context that large objects also consist of many things, as a person has a head, legs, and arms, and a chair has legs and a back. It is not that the “cloud of particles” account is so much incorrect as it is adopting a very unusual perspective. Thus someone on the moon might say that the table is 240,000 miles away, which is a very unusual thing to say of a table, compared to saying that it is on the left or on the right.

None of this is unique to the question of “how many.” Since there is an irreducible element of relativity in being itself, we will be able to find some application to every question about the being of things.

# An Existential Theory of Relativity

It makes sense to view reality in terms of an observer-centred world, because the only things of which you have direct knowledge are your basic perceptions – both inner and outer – at any instant. Anything else that you know – including your knowledge of the past or future – can only be inferred from these perceptions.

We are not trying to establish some silly idea here that things, including other people, only exist when you observe them, that they only start existing when you start observing them, and that they cease existing when you stop observing them. Rather, it means that anything that exists can only be coherently described as existing somewhere in your observer-centred world. There can still be lots of things that you do not know about. You do not know everything about your observer-centred world, and you can meaningfully talk about the possibility or probability that some particular thing exists. In saying this, you are talking about what may be “out there” somewhere in your observer-centred world. You are talking about the form that your observer-centred world may take, and there is nothing to prevent you from considering different forms that it may take. It would, therefore, be a straw man argument to suggest that we are saying that things only exist when observed by a conscious observer.

As an example, suppose you wonder if, right now, there is an alien spaceship in orbit around Proxima Centauri, a nearby star. What we have said does not make it invalid at all for you to speculate about such a thing, or even to try to put a probability on it if you are so inclined. The point is that any speculation you make, or any probability calculations you try to perform, are about what your observer-centred world might be like.

This view is reasonable because to say that anything exists in a way that cannot be understood in observer-centred world terms is incoherent. If you say something exists you are saying it fits into your “world view”. It must relate to all the other things that you think exist or that you might in principle say exist if you knew enough. Something might exist beyond the horizon in your observer-centred world – in the part that you do not know about – but if something is supposed to exist outside your observer-centred world completely, where would it be? (Here we mean “where” in a more general “ontological” sense.)

As an analogy, this is somewhat similar to the way that relativity deals with velocities. Special relativity says that the concept of “absolute velocity” is incoherent, and that the concept of “velocity” only makes sense in some frame of reference. Likewise, we are saying here that the concept of “existence” only makes sense in the same kind of way. None of this means that consciousness must exist. It is simply saying that it is meaningless to talk about reality in non-observer-centred world terms. It is still legitimate to ask for an explanation of your own existence. It simply means that such an explanation must lie “out there” in your observer-centred world.

This seems right, more or less, but it could be explained more clearly. In the first place Almond is referring to the fact that we see the world as though it existed around us a center, a concept that we have discussed on various past occasions. But in particular he is insisting that in order to say that anything exists at all, we have to place it in some relation to ourselves. In a way this is obvious, because we are the ones who are saying that it exists. If we say that the past or the future do not exist, for example, we are saying this because they do not exist together with us in time. On the other hand, if we speak of “past existence” or “future existence,” we are placing things in a temporal relationship with ourselves. Likewise, if someone asserts the existence of a multiverse, it might not be necessary to say that every part of it has a spatial relationship with the one asserting this, but there must be various relationships. Perhaps the parts of the multiverse have broken off from an earlier universe, or at any rate they all have a common cause. Similarly, if someone asserts the existence of immaterial beings such as angels, they might not have a spatial relationship with the speaker, but they would have to have some relation in order to exist, such as the power to affect the world or be affected by it, and so on. Almond is speaking of this sort of thing when he says, “but if something is supposed to exist outside your observer-centred world completely, where would it be?”

Almond is particularly concerned to establish that he is not asserting the necessary existence of observers, or that a thing cannot exist without being observed. This is mostly a distraction. It is true that this does not follow from his account, but it would be better to explain the theory in a more general way which makes this point clear. A similar mistake is sometimes made regarding special relativity or quantum mechanics. Einstein holds that velocity is necessarily relative to a reference frame, so some interpret this to mean that it is necessarily relative to a conscious observer, and a similar mistake can be made regarding quantum mechanics. But a reference frame is not necessarily conscious. So one body can have a velocity relative to another body, even without anyone observing this.

In a similar way, a reasonable generalization of Almond’s point would be to say that the existence of a thing is relative to a reference frame, which may or may not include an observer. As we are observers in fact, we observe things existing relative to our own reference frame, just as we observe the velocity of objects relative to our own reference frame. But just as one body can have a velocity relative to another, regardless of observers, so one thing can exist relative to another, regardless of observers.

It may be that the theory of special relativity is not merely an illustration here, but rather an instance of the fact that existence is relative to a reference frame. Consider two objects moving apart at 10 miles per hour. According to Einstein, neither one is moving absolutely speaking, but each is moving relative to the other. A typical philosophical objection would go like this: “Wait. One or both of them must be really moving. Because the distance between them is growing. The situation is changing. That doesn’t make sense unless one of them is changing in itself, absolutely, and before considering any relationships.”

But consider this. Currently there are both a calculator and a pen on my desk. Why are both of them there, rather than just one of them? It is easy to see that this fact is intrinsically relative, and cannot in any way be made into something absolute. They are both there because the calculator is with the pen, and because the pen is with the calculator. These cannot be absolute facts about the pen and the calculator – they are relationships to the other.

Now someone will respond: the fact that the calculator is there is an absolute fact. And the fact that the pen is there is an absolute fact. So even if the togetherness is a relationship, it is one that follows logically from the absolute facts. In a similar way, we will want to say that the 10 miles per hour relative motion should follow logically from absolute facts.

But this response just pushes the problem back one step. It only follows logically if the absolute facts about the pen and the calculator exist together. And this existence together is intrinsically relative: the pen is on the desk when the calculator is on the desk. And some thought about this will reveal that the relativity cannot possibly be removed, precisely because the relativity follows from the existence of more than one thing. “More than one thing exists” does not logically follow from any number of statements about individual things, because “more than one thing” is a missing term in those statements.

This is related to the error of Parmenides. Likewise, there is a clue here to the mystery of parts and wholes, but for now I will leave that point to the reader’s consideration.

Going back to the point about special relativity, insofar as “existence together” is intrinsically relative, it would make sense that “existing together spatially” would be an instance of such relative existence, and consequently that “moving apart spatially” would be a particular way of two bodies existing relative to each other. In this sense, the theory of special relativity does not seem to be merely an illustration, but an actual case of what we are talking about.

# Semi-Parmenidean Heresy

In his book The Big Picture, Sean Carroll describes the view which he calls “poetic naturalism”:

As knowledge generally, and science in particular, have progressed over the centuries, our corresponding ontologies have evolved from quite rich to relatively sparse. To the ancients, it was reasonable to believe that there were all kinds of fundamentally different things in the world; in modern thought, we try to do more with less.

We would now say that Theseus’s ship is made of atoms, all of which are made of protons, neutrons, and electrons-exactly the same kinds of particles that make up every other ship, or for that matter make up you and me. There isn’t some primordial “shipness” of which Theseus’s is one particular example; there are simply arrangements of atoms, gradually changing over time.

That doesn’t mean we can’t talk about ships just because we understand that they are collections of atoms. It would be horrendously inconvenient if, anytime someone asked us a question about something happening in the world, we limited our allowable responses to a listing of a huge set of atoms and how they were arranged. If you listed about one atom per second, it would take more than a trillion times the current age of the universe to describe a ship like Theseus’s. Not really practical.

It just means that the notion of a ship is a derived category in our ontology, not a fundamental one. It is a useful way of talking about certain subsets of the basic stuff of the universe. We invent the concept of a ship because it is useful to us, not because it’s already there at the deepest level of reality. Is it the same ship after we’ve gradually replaced every plank? I don’t know. It’s up to us to decide. The very notion of “ship” is something we created for our own convenience.

That’s okay. The deepest level of reality is very important; but all the different ways we have of talking about that level are important too.

There is something essentially pre-Socratic about this thinking. When Carroll talks about “fundamentally different things,” he means things that differ according to their basic elements. But at the same kind the implication is that only things that differ in this way are “fundamentally” different in the sense of being truly or really different. But this is a quite different sense of “fundamental.”

I suggested in the linked post that even Thales might not really have believed that material causes alone sufficiently explained reality. Nonetheless, there was a focus on the material cause as being the truest explanation. We see the same focus here in Sean Carroll. When he says, “There isn’t some primordial shipness,” he is thinking of shipness as something that would have to be a material cause, if it existed.

Carroll proceeds to contrast his position with eliminativism:

One benefit of a rich ontology is that it’s easy to say what is “real”- every category describes something real. In a sparse ontology, that’s not so clear. Should we count only the underlying stuff of the world as real, and all the different ways we have of dividing it up and talking about it as merely illusions? That’s the most hard-core attitude we could take to reality, sometimes called eliminativism, since its adherents like nothing better than to go around eliminating this or that concept from our list of what is real. For an eliminativist, the question “Which Captian Kirk is the real one?” gets answered by, “Who cares? People are illusions. They’re just fictitious stories we tell about the one true world.”

I’m going to argue for a different view: our fundamental ontology, the best way we have of talking about the world at the deepest level, is extremely sparse. But many concepts that are part of non-fundamental ways we have of talking about the world- useful ideas describing higher-level, macroscopic reality- deserve to be called “real.”

The key word there is “useful.” There are certainly non-useful ways of talking about the world. In scientific contexts, we refer to such non-useful ways as “wrong” or “false.” A way of talking isn’t just a list of concepts; it will generally include a set of rules for using them, and relationships among them. Every scientific theory is a way of talking about the world, according to which we can say things like “There are things called planets, and something called the sun, all of which move through something called space, and planets do something called orbiting the sun, and those orbits describe a particular shape in space called an ellipse.” That’s basically Johannes Kepler’s theory of planetary motion, developed after Copernicus argued for the sun being at the center of the solar system but before Isaac Newton explained it all in terms of the force of gravity. Today, we would say that Kepler’s theory is fairly useful in certain circumstances, but it’s not as useful as Newton’s, which in turn isn’t as broadly useful as Einstein’s general theory of relativity.

A poetic naturalist will agree that both Captain Kirk and the Ship of Theseus are simply ways of talking about certain collections of atoms stretching through space and time. The difference is that an eliminativist will say “and therefore they are just illusions,” while the poetic naturalist says “but they are no less real for all of that.”

There are some good things about what Carroll is doing here. He is right of course to insist that the things of common experience are “real.” He is also right to see some relationship between saying that something is real and saying that talking about it is useful, but this is certainly worth additional consideration, and he does not really do it justice.

The problematic part is that, on account of his pre-Socratic tendencies, he is falling somewhat into the error of Parmenides. The error of Parmenides was to suppose that being can be, and can be thought and said, in only one way. Carroll, on account of confusing the various meanings of “fundamental,” supposes that being can be in only one way, namely as something elemental, but that it can be thought and said in many ways.

The problem with this, apart from the falsity of asserting that being can be in only one way, is that no metaphysical account is given whereby it would be reasonable to say that being can be thought and said in many ways, given that it can be in only one way. Carroll is trying to point in that direction by saying that our common speech is useful, so it must be about real things; but the eliminativist would respond, “Useful to whom? The things that you are saying this is useful for are illusions and do not exist. So even your supposed usefulness does not exist.” And Carroll will have no valid response, because he has already admitted to agreeing with the eliminativist on a metaphysical level.

The correct answer to this is the one given by Aristotle. Material causes do not sufficiently explain reality, but other causes are necessary as well. But this means that the eliminativist is mistaken on a metaphysical level, not merely in his way of speaking.