As external observers, I think we could equate free will with nondeterminism or randomness. If a system can choose arbitrarily between more than one state with absolutely no outside influence, then by all appearances it has free will regarding that choice.

It's more difficult if we have to consider the internal, subjective state of the system. A radioactive particle probably doesn't experience anything we could identify with when it "chooses" to decay. And the experience we imagine to be free will could in fact be entirely deterministic, even if other aspects of the universe are nondeterministic. But if we can rule out any kind of nondeterminism in the universe, then we can rule out free will.

I kind of feel the exact opposite: free will could only be meaningful if it was completely deterministic.

I mean, think about it for a second. You have a choice between A and B, and you freely choose A. From your definition it seems that if I rewound time to that moment, you might choose B instead. But it's the same situation! If I freely choose to take a walk this morning because it's nice out, I goddamn mean to go out. No matter how many times you rewound time, I would want to go out every single time. It isn't random: there's a reason why I'm doing this, and reasons are never random.

If free will is nondeterministic or random, then I don't want to have free will.

> there's a reason why I'm doing this

The key difference is whether that reason is entirely internal to you or it's the result of external influence. If you always take a walk, an observer could infer that by some arcane law of physics, the sun forces you to take the walk - and they might not be far off.

What I mean by nondeterministic/random is there is nothing someone could know about you, the sun, and the rest of the universe that would let them predict with certainty whether you'll go for a walk or not.

The supernatural ability to rewind time seems like cheating, to be honest. But if that were possible and everything always went the same, then perhaps we could rule out free will (depending on the nature of this time reversal mechanism).

> there is nothing someone could know about you, the sun, and the rest of the universe that would let them predict with certainty whether you'll go for a walk or not.

Nothing someone could know about me? If someone knew everything there is to know about me, I sure hope they would be able to predict everything I will do. Free will doesn't mean freedom from my own nature.

The only way to be perfectly unpredictable is to act at random and without reason. If you act for a reason, then in principle, that reason could be known by someone else, and they could predict your actions. I think that's acceptable: I don't feel that in order for my choices to be free, my nature and my reasons must be unknowable to anyone but myself.

> But if that were possible and everything always went the same, then perhaps we could rule out free will

According to your definition, yes. Not according to mine. So I guess we made the OP's point ;)

If someone can predict everything you will do, they can manipulate events so you will do their bidding according to their predictions. That doesn't leave any room for free will. Of course if they're part of the same fully determined system, then they're also just doing what they were destined to do. You would feel like you're making your own decisions, and they would feel like they're manipulating you, but it's all illusion.

I don't think that's relevant. It may be true that we do not have free will in prison, nor in that very contrived scenario you've cooked up, but that has no bearing on whether we have free will or not when we aren't imprisoned or manipulated.

The ability to choose between options without the choice being determined by prior conditions or influences.

It would seem to me that the act of choosing isn't but deciding which alternative is preferred. And so impossible to separate completely from prior conditions or influences. So the question would then become what does "determined" mean in your definition?

The definitions of 'determined' and 'influence' are at odds with one another in your definition.

If a person's choice is mostly determined by the state of their brain at the moment of choosing, would that count as a "prior condition"?

It would mean the choice is mostly determined by their "self", but the definition you give isn't clear about whether that would count as free will or not.

so then what else informs a free agent's choice?

And if you have a free agent without prior conditions or influences - how was it made?

An agent's ability to do and not do without external influence or coercion.

The other side of this though is if the agent believes he or she has the ability to do or not do, but actually doesn't, is it still free will? An example being you enter your office with the intention of working for five hours. Without realizing it, the door locks behind you from the outside, leaving you effectively trapped. Even if you never attempt to leave the room, are you staying at your own free will?

I agree that "An agent's ability to do and not to do without external influence or coercion." in the context of a social or political theory of free choice.

But in simple model, of just a world, where one only has configurations of atoms (or configurations of some substance or etc), there's nothing uniquely determining what's internal and what's external, what's an agent and what's not. So "free will" winds-up achingly ill-defined/under-determined here.

I think your definition is further relevant in that a lot of arguments confuse an ontological model and with a social/political model. And this could well be natural - as social beings, it seems like we tend to both model the world and see agents within it and so saying "in this model, you have choice but in this other model, you and choice don't exist" is highly counter-intuitive to an average human.

> there's nothing uniquely determining what's internal and what's external, what's an agent and what's not. So "free will" winds-up achingly ill-defined/under-determined here.

This is really interesting. Thanks for the reply.

Wittgenstein anyone?