Free Will

[Pyrrho]

Or in other words, due to the structure of your body.  You did not choose to have a hand in the first place, or nerves, or a brain, etc.  That is all due to things prior to your existence. Whether that is due to "determinism" or random chance or whatever, clearly, you did not choose it.  Everyone of sense knows that, so why is it that people pretend it is not the case?*  

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*As is often the case, the answer to the question resides in the question itself.  It is not everyone, but everyone "of sense" that was specified, and it is those who are lacking in sense who fail to realize such obvious facts.

I suppose one reason people may doubt that is the case is that they're not materialists, and how one defines being or self - whether or not mind emerges as something distinct from a given sum of physical parts, or is itself a physical process, or if there is something above and beyond the objects of sense that is inextricable from reality or the experience thereof - probably has implications for their view of the will i.e. what it consists of and how it is exercised.

Whether materialism is correct or not makes no difference.  If substance dualism is correct, you still have a hand that you did not choose to have (unless you happen to have no hands, but then we can just change the example; the point will still be the same), and it is still connected to your mind such that you are unlikely to want to stick your hand in a fire, due to the nature of your hand and the nature of the connection between your hand and your mind.  The only difference is the idea about what the mind is, that it is immaterial rather than some processes in a brain.  But that makes absolutely no difference for the pain of sticking your hand in the fire, the consequences to your hand for sticking it in a fire, etc.  You still did not choose to have the hand, and the connection of the hand to your mind, and that you have a hand with a connection to your mind is why you don't want to stick it in a fire.  In other words, either way, what you will can be traced to something that you did not choose.

If idealism is correct, the same idea still applies, the only difference being that the description of what your hand really is changes.  Again, sticking the 'immaterial' hand into an 'immaterial' fire still hurts the same, etc.

And no matter which of these, or any other metaphysical claptrap one wishes to propose, we are still left with the fact that one did not choose to come into existence, as one did not exist before one existed, and so one was not choosing anything at that time.  And after one begins to exist, it is too late for one to choose how one initially comes into existence.  One still starts with qualities that one did not choose, and one chooses things due to the qualities one has.  (If one did not, then one would not be choosing at all, but some other force would be acting aside from one, or random events would be taking place, or some other thing that is not one choosing.)  Indeed, this idea extends further, in that a being that has always existed could not have chosen its beginning nature either, as it had no beginning and consequently nothing could have chosen its beginning.  But that extension is of no practical importance for humans, unless one is going to pretend that a human has existed eternally.  But even with such a pretense, it would make no difference for the claim I am making about your hand and why it is that you probably do not will to stick your hand in a fire.