Monday, July 26, 2010

Essentiality of origins, determinism and free will

If determinism is true, then any possible world in which at t0 I act differently from how I actually act at t0 is a world where either (a) the laws are different from the actual world's laws or (b) the laws are the same but the past is different at every time prior to t0. In case (b), it follows that my own causal history will be different in that world. But if essentiality of origins is true, my own causal history could not have been different. Therefore, if essentiality of origins and determinism are both true, then any possible world in which at t0 I act differently from how I actually act at t0 is a world where the laws are different from how they are.

On the plausible assumption that I cannot do something the doing of which entails that the laws are other than they are at @ (where "@" names the actual world), it follows that if determinism and essentiality of origins are true, then I cannot act otherwise than I do.

Or, to put it differently, if essentiality of origins holds, the compatibilist's "Had I wanted to, I would have acted differently" conditionals are counter-nomic. But it is most implausible that a counter-nomic conditional would suffice to capture our "could have done otherwise" conditionals.

Therefore, if essentiality of origins is true, either determinism is false or we are not free.

5 comments:

BernardZ said...

This sounds like a classical Islam argument whether determinism and free will are incompatible?

I make choices, just because God could determine what I was going to do before I did it does not mean that I am not making choices freely.

James Bejon said...

But it is most implausible that a counter-nomic conditional would suffice to capture our "could have done otherwise" conditionals.

Wouldn't a compatibilist have to claim something very much like this regardless of whether or not he holds to the essentially of origins?

Alexander R Pruss said...

JB:

No, for if essentiality of origins is false, the conditional wouldn't be counternomic--it would be backtracking-or-counternomic.

James Bejon said...

I see--I think. You mean something of the form

If P had decided to do Q as opposed to Q', then he would have had brainstate B as opposed to B'?

(assuming for the moment that naturalism is true)

Alexander R Pruss said...

My argument fails. Suppose the initial conditions include a region R of spacetime such that R is in the backwards light cone of me at age five but not in the backwards light cone of me now. Then events in R won't affect my existence but will affect my action. Imagine, for instance, that a counterfactual setup in R triggers a supernova that appears in the sky just as I am praying at age 5. This might be taken by me as a sign from God, resulting in higher moral development, and leading to me now making better choices than I do. Hence my current poorer choices would have a noncounternomic backtracking alternate possibility.