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Comment by pjlegato | Hacker News Reader

As David Hume points out, you don't actually know you'll be hungry tomorrow. You assume you will be based on induction from similar past events, but this is not certain. (He does concede that it's reasonable to plan as if it were a certainty in such cases, in the absence of any falsifying evidence.)

The famous counterexample metaphor is farmyard turkeys. For months, for their entire lives, the turkeys observe the diligent farmer bringing food and water, providing for their every need so that they don't have to do anything. On the day before Thanksgiving, a turkey philosopher confidently declares that, based on this prior evidence, we can conclude that the farmer, their great benefactor, exists only to serve and further the interests of turkeydom.

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Perfect. The philosopher turkey views the past as causing the future while in fact the farmer’s future meal caused the turkey’s past experiences. A great example of how serious an error rejecting reverse causality can be.

The turkey is simply wrong in its inductive reasoning. Your hunger tomorrow will be a consequence of the forward causal process of metabolism. That the turkey's demise occurs specifically on thanksgiving day is partly determined by a cultural attitude having its origin in past events.

Aristotle, of course, used a broader ontology of causes than is commonly used today, but there should be no confusion if we are careful to define what we mean. In particular, final causes are more commonly regarded as psychological attitudes, whereby if someone acts now to bring about a certain circumstance in the future, the circumstance is caused by what they were thinking prior to the action.

Hume uses the example of the sun rising: though the sun has (so far) always risen in the east, there is no logical reason to assume that it will _necessarily_ do the same tomorrow tomorrow. Though we can reasonably plan for this as the most likely scenario based on available evidence, it is not _necessarily_ going to happen.

There is, likewise, no logically necessary reason to assume that that causal process of metabolism will continue to work tomorrow as it always has in the past, though it is indeed reasonable to prepare for that outcome as the most likely outcome.

That is true, but here I am discussing the different issue (raised by simple-thoughts) of whether causality can work backwards in time.

If someone buys something to eat at breakfast tomorrow, but dies before then, there was no future event to cause the purchase.

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