The notion that free will does not exist.

You argue for determinism. I don't believe people's decisions are random (I believe in choice; I'll defend it later), but even random actions are far more likely than the immutable causal change you suggest. A basic choice model shows no causal chain can be perfect. Assume for simplicity a situation where someone, Bob, has no more than two options - press a red button or press a blue button. According to your reasoning, it is theoretically possible for an algorithm to consider Bob's life history, genes, present mental state etc. and calculate his choice. Let's say it calculates "red." Now we add to the factors the algorithm considers: "telling Bob he will press blue but should try to press red." Your argument suggests the algorithm will still calculate an answer, red or blue. If "red," you are saying that Bob cannot press red, even if he tries? If "blue," you are saying Bob cannot disobey the instructions and press blue, even he tries? Thought shows both restraints are impossible, whether we define Bob's action as the result randomness or choice. First, let me defend randomness. Determinism gained popularity when people learned about the laws of physics and physical causality. Deeper science, however, specifically quantum mechanics, proves that some events in the universe really do occur randomly. Fundamental processes like a single nucleus's decay can at best have a probability of occurring for any one instance; no single nucleus will definitely decay at any given time, even if we try to encourage it. And not only are we unsure whether a given electron acts as a particle or a wave, we realize it is neither till we observe it, at which point it randomly acts as one of the two. Randomness at a rudimentary level necessarily creates randomness on a larger level, unless you allow for an outside actor with choice, which again violates determinism. To defend choice, I'll go from the scientific back to the philosophical. Consider the implications of attributing individual action to involuntary causes (or, for that matter, to randomness)? You preclude morality. This means preclude responsibility for harming others, and besides being intuitively abhorrent, you thus demand abandoning the punitive justice system and discipline in general. You also preclude credit for individual accomplishments, and thus rule out compliments, awards, property rights, intellectual property rights and capitalism. These issues don't prove free will, but I want to hear your responses to them. Do you accept them as just, or do you admit a logically inconsistent position? Finally, I'd like to prove choice by giving an example of limited choice. People with Tourette's Syndrome or addictions have greater difficulty exerting their will than those without, right? But while these conditions seem in themselves prime examples of free will's absence, their existence proves how will exists in varying degrees in different people. If free will didn't exist, nothing would distinguish us from people with involuntary tics, who wish to control their actions but can't. Clearly something does distinguish us from them, which proves we can exert our will. Now to address your points. They're defensive - you're argument seems to be, "An argument for free will has flaws, therefore determinism exists." ---"Is it not evident a posteriori that all actions of will are determinable retroactively? No. We can determine which action occurred, but not why. Take a single atom's decay for instance. Most of your argument assumes we can assign reasons for all occurrences, but we can't, and you've given no evidence that we can. ---"To insist that will may be indeterminable before the choice was made is to insist that there has to be some spontaneous element...If this spontaneous element is to truly be spontaneous, it must be random." Actually, no. It only must be random if you presuppose the nonexistence of choice. Choice is a spontaneous, non-causal external element. You assume the nonexistence of choice to prove its nonexistence. That's circular reasoning and fallacious. ---"Occam's Razor is useful...indeterminable free will takes far too many presumptions." You're saying here that free will is impossible because determinism is simple? We prefer simplicity when explaining phenomena, but that does not mean simpler explanations are right. Occam's Razor says we should eliminate assumptions that make no difference in the observable predictions of a hypothesis, but the existence of an outside agent makes a difference all right - it's the most crucial factor in question. ---"'Choice' is simply an act of determinable causality, and that all 'choices' are made from necessity and will." Apply that to Bob? The rest of your case seems to depend on your first few assertions. (By the way, I leave for vacation Saturday morning. Can we finish this before then?)