If neuroscience were to prove that one particular person has free will, does that imply that everyone else in the world would have to have free will as well? If neuroscience tests show that not everyone has free will, how would philosophers explain that other than redefining free will?

I notice that your question leaves "free will" undefined, so let me propose the definition found at merriam-webster.com: "the ability to choose how to act; the ability to make choices that are not controlled by fate or God." I presume that no one imagines that neuroscience will prove that some of our choices are controlled literally by fate or God. So if neuroscience is to show that some or all of us lack free will, neuroscience must show that some or all of us lack the ability to choose how to act or the ability to make choices. I don't think we need neuroscience experiments to show us that some people lack free will in the sense just defined: for example, people who are in the midst of drug-induced mania or a psychotic episode. To show us something we didn't already know, neuroscience would have to show that people in general typically or routinely lack free will. Some neuroscientists do claim to have shown that, but their arguments are woefully unpersuasive (in my judgment and in the...

I have a question about causality solely when it comes to human behavior. Suppose I argue that the presence of oxygen on Earth was the cause of an office building on fire. It is certainly true that if there had been no oxygen on Earth there would have been no fire. It is also true that if there had been no arsonists or negligent persons, nor any flammable material, there would have been no fire. So is it true that when it is assumed that one of several necessary conditions was the sole and exclusive cause of an effect, then the reasoning is fallacious due to the possibility that humans might have free will which somehow shifts responsibility away from nature or scientific processes?

Assuming I understand it, the reasoning you described is fallacious regardless of anything having to do with human free will. True, the presence of something combustible is a necessary (but fortunately not sufficient!) condition for the occurrence of a fire. But if I were to infer from that fact alone that the presence of something combustible was the sole cause of the fire , my inference would be laughably bad: indeed, onlookers would probably construe it as a joke. In any case, it would be evidence that I don't really possess the concept of causation. I think that a related but different fallacy is often committed by those who say that the physical necessitation of a human action always makes the action unfree. It's the fallacy of assuming that the physical necessitation of an agent's action always bypasses the agent's deliberations. If causal determinism is true, then my decision to respond to your question was physically necessitated by events that predated my birth. But that doesn't imply...

If we have no free will, then is the entire legal system redundant since no one can be held accountable for anything since no one has control over their own actions?

Those like me who are compatibilists take the view that the truth of determinism would have no consequences for law and morals. Like Jonathan, I too am a compatibilist, and I agree with what he says in the italicized statement above. However, the questioner asked about the effect on the legal system of (1) the total absence of free will, not (2) the truth of determinism. I agree with Jonathan that (2) has no consequences for law and morals. But (1) does. One consequence of (1) for morals is that no actions are morally right or wrong. Furthermore, our current legal system routinely assumes that defendants are morally responsible for their actions and able to conform their conduct to standards of right and wrong. If that assumption is false, then our current legal system is corrupt, or at least unfair, assuming that it's unfair to hold people morally responsible when in fact they're not morally responsible. Is hard determinism supposed to imply that nothing is unfair? If hard determinism...

If no one can legitimately be held accountable for anything, then I think the Anglo-American legal system (the only legal system I know at all well) is worse than redundant (and strictly speaking not even redundant): it's fundamentally corrupt. Indeed, it's hard for me to imagine any legal system that doesn't presume that we have control over at least some of our actions. Even a system that punishes solely for the sake of deterrence or rehabilitation needs to presume that we can control our actions, at least sometimes, in response to examples that are meant to deter us, or as a result of programs that are meant to rehabilitate us.

There has been much made of Hawking and Harris using brain scans to demonstrate a deterministic explanation of "free will". My question is, how do they treat a case where I think about moving my arm, but don't? How can the experiment they site test thoughts, subjective experience, etc. which do not lead to any outward physical effects? Must we accept that for all cases of mental phenomena that the brain scan test constitutes a proof?

Must we accept that for all cases of mental phenomena ... the brain scan test constitutes a proof? I think the important philosophical question here is "A proof of what?" Suppose that science did somehow establish that all of our choices are causally determined by our earlier brain states. According to compatibilism , that result wouldn't threaten free will at all, and according to many compatibilists it would be good news indeed for free will. Before we get too hung up on whether brain scans are evidence in favor of determinism about human choices, let's ask the prior philosophical question "What difference would that make for free will?" You'll find this issue discussed many times on this website, including here: Question 5451 Question 5711

Why should I be convinced by a hard determinist's argument against free will if, assuming his position is true, I am simply determined by causes other than myself to believe in free will? And I also wonder if there are professional philosophers who are hard determinists who try to convince other people of their view if in their view all people are determined (by causes other than their free choice) to believe whatever they presently believe.

Your question seems to presuppose that one chooses whether to be convinced by an argument or whether to believe that one has free will. I don't find that presupposition to be psychologically plausible, and indeed it might be conceptually incoherent. Besides, wouldn't you rather form your belief because of a compelling argument than because of something else? You'll find relevant discussion in this online article . In any case, determinists -- who say that all events, including all human choices, are causally determined by prior conditions -- can grant that one chooses whether to be convinced by an argument or whether to believe that one has free will. According to determinism, such a choice will be causally determined by prior conditions, including any arguments to which the chooser has been exposed. It could be that the logical virtues of some argument are among the conditions that cause someone to choose to accept its conclusion. So I see nothing paradoxical about a (hard or soft) determinist...

Why don't determinists believe, at least partially, in the notion of free will? If all events are simply outcomes of antecedent choices and events, wouldn't my decisions now affect me, to some degree, in the future? Thanks for considering this question, as rudimentary as it may seem.

Many philosophers believe in both determinism and the existence of free will. Even more philosophers accept at least the compatibility of determinism and free will: they're known as 'compatibilists' (see this link ). Some philosophers go so far as to say that free will requires determinism: see this link . Accepting determinism doesn't by definition imply any particular stand on the existence of free will. That's why the term hard determinist is reserved for those who deny the existence of free will because they accept determinism. You may also want to look at these questions recently answered on this website: 5408 ; 5397 ; 5349 ; and 5178 .

Compatiblism is attractive because it finds room for human freedom in a deterministic world. But objections that compatiblism is evasive or incoherent strike me as persuasive. Setting aside the indeterministic defense of free will, how might the hard determist endorse the claim that humans generally do bear moral responsibility for their actions? Or would the hard determinist have to bite this bullet and conclude that moral responsibility is illusory if we have no free will?

As I understand it, hard determinism by definition holds that because determinism is true, no one is morally responsible for his/her actions. That is, hard determinists are simply incompatibilists who accept determinism. See the definition of 'hard determinism' given at this link . According to that definition, hard determinists hold that human agents never bear moral responsibility for their actions. By 'hard determinist', did you perhaps mean to refer to a compatibilist who accepts determinism, or perhaps just anyone who accepts determinism? I'd be interested to know which arguments persuade you that compatibilism is evasive or incoherent. I haven't found any that persuade me of that. You say that compatibilism 'is attractive because it finds room for human freedom in a deterministic world'. I find it attractive because it concentrates on the ingredients that actually seem to bear on an agent's moral responsibility, discovering thereby that indeterminism isn't one of those ingredients.

There are many questions and answers here about free will and its importance for moral responsibility, and about how free will is consistent with the scientific view of the world. I would like you to consider the idea that even if there is free will, many human actions are anyway caused by circumstances, and we should try to refrain from blaming people. It is known that when economy goes down, crime rates increase. Violent criminals were often victims and spectators of violence in their childhood. Child molesters were often sexually abused when they were children. Religious terrorists were born and brought up among followers of their religion and were often led to terrorism by people around them. Of course, many people experienced more or less the same circumstances and didn't become criminals, but that's easy to say when you're on the right side of statistics, isn't it? And circumstances are never really the same. I know a 5-year old boy at my daughter's pre-school who doesn't seem to be growing properly...

You're right: many questioners have asked about free will, moral responsibility, and their consistency with a scientific view -- determinism -- that sees the world as governed by deterministic natural laws. These topics are important philosophically and have serious practical implications. A minority of the philosophers who specialize in these topics (see this link ) say that deterministic natural laws would rule out free will and moral responsibility: they're incompatibilists . Some of those incompatibilists also accept determinism -- they're hard determinists -- and therefore they say that no one ever acts freely and no one is ever morally responsible. According to hard determinists, President Obama is no more responsible, morally -- and is no more blameworthy -- for any of his most carefully planned decisions than is an addict who assaults someone while whacked-out on PCP. They say that determinism by itself rules out moral responsibility and blameworthiness, regardless of...

Is libertarian free will a necessary assumption for any decision theory because “one has to suppose that one has a choice to make”? It seems to me that decision theories needn't rely on the formulation that agent1 can x or ~x regardless of preceding states-of-affairs, but that it can equally well rely on agent1 x'ing because state-of-affairs1 determines that agent1 x's or agent1 ~x's because state-of-affairs2 determines that agent1 ~x's. The point is not whether the agent can make that decision with exactly the same preceding state-of-affairs, but whether the agent could make both decisions, however the decisions are brought about. My reason for this position is that if libertarian free will is a necessary assumption for any decision theory is correct, determinists should not make normative suggestions ever. One would suggest this perhaps, because they'd claim determinists cannot ever make normative suggestions coherently. I believe this is wrong because normative suggestions a determinist makes...

Like you, I don't see why rational decision theory must assume that agents have libertarian freedom. Indeed, if memory serves (it's been a while), Richmond Campbell argues that fundamental principles of rational decision theory rule out libertarian freedom on the part of the agent: 'Moral Justification and Freedom', Journal of Philosophy 85 (1988): 192-213. I think you're right to emphasize that if there's a deterministic causal chain leading to an agent's choice, that chain can, and typically will, include the agent's rational deliberation about which choice to make.

It has been said that if there is human freedom, then we are responsible for our actions. By this, it seems natural to suppose that "given that there is no human freedom (let's just suppose for the sake of argument) then it would follow that we are not responsible for our actions." But this seems an instance of what is called the "fallacy of denying the antecedent". Is this really an instance of the fallacy or is it an exemption to the case because personally I don't see any error in the form of the argument.

Translating the argument into symbolic terms quite literally, we get this: 'If F, then R. Not F. Therefore, not R.' That form of argument does indeed commit the fallacy of denying the antecedent: the premises don't logically imply the conclusion; the truth of the premises doesn't logically ensure the truth of the conclusion. The first premise says that F is sufficient for R; it doesn't say that F is necessary for R. In that case, R can obtain even if F fails to obtain. My hunch is that you're interpreting 'If F, then R' as 'R if and only if F': you're interpreting the conditional as a biconditional , i.e., as the claim that F is both necessary and sufficient for R. 'R if and only if F' and 'Not F' together imply 'Not R'. Your interpretation is understandable, because conversationally we often do intend to assert a biconditional when we use conditional language. A parent's 'If you clean your room, you can watch TV' usually means 'You can watch TV if and only if you clean your room...

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