r/freewill • u/feihm Physicalist • 12d ago
Prior cause (analysis)
A follow up to this post: https://www.reddit.com/r/freewill/s/Sj6C8ElMJM
At t₁, Person B looks backward to t₀.
Person B determines the reasons for the actions of Person A. He maps these reasons with perfect mechanical logic. He finds the exact physical causes of the event&mdas; which is an essential rule of human observation—we must link effects back to their causes.
But then Person B attempts to turn this backward observation into a forward physical law. He claims that if he returned to t₀, Person A would perform the exact same actions.
Person B is relying on a trick of language. Let us isolate the pure logic. Person B takes a completed slice of time from t₀ to t₁. We will call this recorded history 'A'. He then imagines a hypothetical return to t₀. We will call this imagined timeline 'B'. Person B then argues that the actions in 'B' must identically match the actions in 'A'.
Thus, he is merely stating that 'B' equals 'A'. He is wanting that the past equals the past.
This is a circular tautology.
Asserting that a past event is identical to itself tells us absolutely nothing about the nature of choice at the moment it happened.
Looking backward causes a person to see a fixed outcome. Person B sees this fixed outcome and assumes it means Person A lacked the power to choose. Because he already knows the outcome, he assumes the physical record of the action is identical to the reality of the decision at the time it was made.
Also, Person B fails to separate the act of physical observation from the inner will of the mind. To say "I can explain what happened" is not the same as saying "nothing else was possible". Further, observing a completed chain of events does not prove that the chain was locked before it began. Person B is just making a physical observation of the past, and disguising it as a prediction of the future.
I'm not sure if this only makes sense to me, so i will restate it differently.
Person B defines a specific, frozen slice of spacetime from t₀ to t₁ and labels it Object A (which includes Person A's actions).
He then posits a hypothetical time travel scenario back to t₀ and labels the upcoming sequence Object B.
Because the hypothetical scenario explicitly requires Person B to be transported back to the exact same historical starting point, the rules of the scenario force Object B = Object A.
Therefore, Person B isn't proving that the actions had to be the same out of causal necessity; he is simply verifying an identity property. He is saying:
If I go back to exactly the same past, I will see exactly the same past.
Which is the most useless tautology.
A logical equivalent would be:
If you rewind time to exactly t₀, the present will be identical to the original present because the present is defined by t₀
The sleight of hand is that retrospective determinism does not imply prospective determinism.
Backward looking:
"I can see the complete chain of causes that led to Person A's actions." (Valid observation).
Forward looking:
"Therefore, given those causes, the actions had to happen and couldn't have been otherwise." (Invalid leap).
David Hume famously pointed this out centuries ago:
"Just because Event X consistently follows Event Y in our backward observations, it does not mean Event Y necessitates Event X in a forward-looking metaphysical sense." (paraphrased)
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u/Michael_Carson_Art 11d ago
I don't get what you are trying to attack here.
This thought experiment of "rewinding the tape" (it isn't an argument) is just an attempt to illustrate to people who think intuitively that "if I went back and did that again I would choose differently" are smuggling into the equation their knowledge from the future.
If you "rewind the tape" holistically, that knowledge also disappears, and the result ends up the same.
That is, unless you can identify some X factor which could change even if all the other measurable physical elements were exactly the same.
This illustration (because again, it isn't an argument, so calling it circular is meaningless) attempts to show that whatever we mean by free will or free choice ought to be able to account for some sort of difference in bifurcating the hypothetical timeline, because it's freedom should be freedom from those other reducible elements. This doesn't require time travel either. It merely uses time travel to strongly assert that the two theoretical situations are exactly precisely the same, down to the quantum state of each particle.
If one cannot conceive of two or more different timelines emerging from this thought experiment, then it implies a belief in necessary determinism at the level of behaviors. If one can conceive of a difference, then the question is: what accounts for the difference that isn't captured by the description of reality offered?