# Counterfactuals and Causality

People have frequently noted some connection between counterfactuals and causation. While it seems backwards to suggest that causation should be defined in terms of counterfactuals, it is reasonable to connect the two concepts, and explains why some counterfactuals are more reasonable than others, as we noted in the last post.

For example, “If I dropped this cup, it would fall to the floor,” is more reasonable than “If I dropped this cup, it would fly up to the moon,” because we are considering the operation of causes like gravity which could cause falling to the floor, and which could not cause (merely by dropping) an object to fly to the moon. In particular, since causes eliminate alternatives, they give us a reason to say “this would have happened rather than that.”

Nonetheless, we cannot get any sort of absolute determination out of this. One would attempt to get a determinate outcome by specifying the counterfactual as clearly as possible: “If I dropped this cup, and everything else was the same.” The “nearest possible world” idea is trying to get at this. However, this is not in fact completely determinate because “everything else” can’t be entirely the same, and what else needs to change is not determinate. In order to drop the cup, there would need to be a course of events that led up to the dropping, and there are many different courses that could have done that. The same thing will happen if you to specify exactly what led to the dropping of the cup; there will need to be something that led to your specification. Thus, at the very least, you will not typically be able to get absolute determination in this way.

Naturally, there is nothing to prevent us from coming up particular examples where we can get complete determination by using something which is always true anyway, or by using logical implication from the counterfactual, e.g. “If I dropped this cup, 2 and 2 would still be 4,” or “If I dropped the cup, it would have been dropped.” But these are not typical cases.

# Counterfactuals as Historical Fiction

Suppose someone reading Anne of Green Gables asks a question about what happened before the story begins. For example, what did Anne have for lunch 37 days before her arrival in Avonlea?

It is easy to see that this question does not have one true answer. There is no such thing as what she really had for lunch, because it is a story, and that meal is not included in it. On the other hand, despite the lack of any absolute truth here, some answers remain more reasonable than others. For example, “She had salad,” is a more sensible answer than “she ate crushed glass that day.” Just as I said in regard to “why” something is the case, one can give a partial answer, in the sense of showing that some options are more intelligible than others, without being able to exclude some options entirely.

These same things will apply to questions about a work of historical fiction, although the intended historical context will provide additional ways to show that some answers are more sensible than others. Thus if a story is set in ancient Rome, the claim that someone had corn for lunch is unreasonable due to the historical context, although not as unreasonable as some other possibilities that you could suggest.

Now consider a counterfactual question about your current situation: “What would you do if it were 120 degrees Fahrenheit in your house?”

There is no fundamental difference between this and the case of historical fiction. In effect, we just created a story about you: “It was 120 degrees in your house. You…”

Like the case of historical fiction, some answers will be more sensible than others, but there is no thing that you really would do in that situation. The story didn’t really take place, but if it did, it would have taken place with a lot more concrete detail, and that concrete detail could determine the specific answer to the question. If Anne of Green Gables were a true story, her concrete situation would have determined what she had for lunch that day. And if it were really 120 degrees in your house, what you would do would depend on how and why things got that way, as well as other factors in your concrete situation.

Some philosophers have spent a lot of time on this kind of counterfactual question, apparently largely from a desire for absolute answers. For example, some suggest that a counterfactual is true if the claim is true in the nearest possible world where the antecedent is true. In a similar way, Molinists argue that in order to be omniscient, God has to know what you would do if it were 120 degrees in your house, and that it must be one specific thing, so that there is one thing that you really would do in that situation. They call this kind of knowledge “middle” knowledge, namely something in between knowledge of what actually is and knowledge of what merely might have been.

All accounts of this kind are wasted effort. The brief account above is sufficient.