Friday, January 30, 2009

An argument for libertarian free will

The following homely, unoriginal, and obvious argument seems not be a hot part of current discussions, but I've just been struck by the obviousness of its soundness. Start with the following obvious fact:

  1. If I am to any degree responsible for a decision or mental state E, then either E is identical with or the result of a libertarian free choice by me, or E is at least in part the result of an earlier decision or distinct mental state for which I am to some degree responsible.
Add the following very plausible premises:
  1. I have made only many finitely many decisions and have had only finitely many distinct mental states.
  2. There in fact are no causal circles.
It follows from (1)-(3), perhaps with some tweaks (I'm being rather rough here), that if I am to any degree responsible for any decision or mental state, then I have made a libertarian free choice.


Matthew said...

That looks quite interesting. Maybe you should post it at the Prosblogion?

wrf3 said...

I strongly dispute the "obvious fact". We are not responsible because of any innate freeness, but rather by divine fiat.

Alexander R Pruss said...

Are there any preconditions for the fiat or is it entirely dependent on God's will? E.g., could God hold someone responsible for something that the person did not in fact do? Could God hold someone responsible for something that isn't a voluntary action at all--say, a twitch? If the answers are negative, then there are constraints on what God, presumably in light of his omniscience and justice, can hold us responsible for. And if there are such constraints, then (1) could be among them.

Alejandro said...

Dennett suggests a similar argument to yours and refutes it with an analogy with the argument:

1.If an animal is a mammel, then either it is the first mammel or it had mammels as its parents.

2.There have been a finite number of mammels.

Hence there must have been a First Mammel. But rather, there has been instead a gradual transition from non-mammels to mammels.

Since in your argument in both uses of "to some degree responsible", the degree might not be the same one, the compatibilist is open to saying that as we go back in time, into my childhood, the degree of responsability I had for my acts faded gradually, but that a gradual transition from non-responsible to fully responsible acts is possible.

Or, if you insist on being mathematically rigorous and saying that a truly gradual (continuous) transition is not possible over a finite number of discrete states, then I could instead deny your first premise for some action in early childhood, saying that when the degree of responsability of an action is very very low, then it need not have been preceded by another responsible action (nor, of course, be a libertarian choice).

Alexander R Pruss said...

Do you have a reference for the Dennett discussion?

(Well, I actually am inclined on Aristotelian grounds to think there was a first mammal, but that's a different story.)

It seems to me that it is a serious mistake in philosophy to confuse qualitative and quantitative differences. For instance, a transition from a non-conscious being to a conscious one is no less mysterious when there is just a tiny bit of consciousness there. To say that consciousness is not a problem because initially there was just a tiny bit of it doesn't help at all. In Haldane and Smart's _Atheism and Theism_, Smart responds to Haldane's design argument from intentionality by talking of animals having proto-intentionality or something like that. Well, either proto-intentionality is intentionality (of some rudimentary sort) or it's not. If it is, then the problem has just been pushed back; if it is not, then the concept is useless.

In any case, I still think the intuition that one cannot be at all responsible for something that is not agent-caused and comes from mental states and decisions that one is not at all responsible for is completely right. It does not matter what degree of responsibility there is.

We can make this mathematically rigorous. Let S be the set of times at which one is responsible to any degree for anything. Then either S has a first member or it does not. If S has a first member, then on the deterministic hypothesis we have a state of being responsible which is caused by states that we are not responsible for. If S does not have a first member, then assuming one continues to be responsible for something that one was once responsible for, there will be a last time t0 at which one was not yet responsible for anything. At every time after t0 (maybe until death), one is already responsible for something. So, somehow, the state of the world at t0 causes one to be responsible at all later times.

Alexander R Pruss said...

Here's a link to a pertinent quote from Dennett.

Alexander R Pruss said...

I posted an improved version of the argument here.

Nightvid said...

The inclusion of the world "libertarian" in premise 1 makes your argument question-begging and empty.