It is difficult to find a more universally captivating philosophical issue than free will. Furthermore, you’d be hard pressed to find a more perennial topic consistently commented upon by the scientific community. Readers of these scientific pronouncements will know that the notion of free will is usually met with skepticism or outright denial. Unfortunately, these judgments are almost always premature and lacking justification, given that the authors seldom understand the issues they are trying to evaluate. The problem is unsettled, but there are quality arguments that support the conclusion of free will deniers. I’d like to briefly describe the basic structure of the best argument against the existence of free will.
The trivial and uninformative version of the argument is as follows (this basic argument will be helpful in the long run):
1. If free will exists, it is either consistent with determinism, indeterminism, or both.
2. Free will is inconsistent with determinism
3. Free will is inconsistent with indetermism
4. Therefore, persons lack free will.
The very idea of free will is notoriously vague, but there is a general agreement among philosophers that free will is the capacity to make morally responsible choices. Or, free will is the control condition for moral responsibility. The most popular position in the community is called compatibilism. Compatibilism merely means that free will is consistent with determinism. Determinism is the thesis that the past and the laws of nature causally necessitate the future.
There are two primary strategies for denying compatiblism. The first is that determinism denies agents alternative courses of action (disciples of Lewis ought to be reminded that it’s possible to have an ability, yet lack the opportunity to exercise it). This move leans on the intuitive Kantian idea that ought implies can; this Kantian principle means that we can only justify holding someone responsible for an act if they could have done otherwise. Technicalities aside, the objection is essentially that there’s no in-principle moral difference between being necessitated into an action by the causal structure of the world than by gun-point.
A recent popular alternative for affirming or denying compatibilism is the emphasis on sourcehood. This notion takes the idea of free choice to be a matter of being the genuine source of one’s actions. So in the compatibilists conception, you may be determined to make particular choices, but you are determined by your own nature, and as long as your aren’t the victim of responsibility undermining compulsions and conditions, your unique place in the causal chain supplies sufficient control to justify our ordinary moral judgments. The free will skeptic will counter that your position in causal space was entirely out of your control. Your capacities and preferences are the product of a very long chain of cosmic and evolutionary processes, in which you had no say. Essentially, if determinism is true, then local sourcehood never obtains; the source of any occurrence is wholly global.
Assuming these lines of reasoning work, the free will affirmer is afforded two alternatives. Either we have free will in virtue of our neural processes being partially indeterministic, or there is something called agent causation. In the first case, we have free will because we can make decisions that literally could go multiple routes; the causal nature of the universe doesn’t guarantee a particular outcome. Although it may seem plausible that free will is secured on this picture, this notion fades once we remember how free will is being understood – the capacity to make morally responsible decision. For example, let’s image a person positioned and ready to assassinate the popular scientist, Sam Harris. This man is annoyed and exceptionally frustrated with Harris’s facile arguments against free will and thinks it’d be better if this Ben Stiller clone took a few rounds in his insufferably smug face. What’s at issue is that if his decision making processes are partially indeterministic, then it is in a significant sense a matter of chance whether this person pulls the trigger. The problem is that this is inconsistent with our ordinary judgments of responsibility where we praise or blame an individual based on them controlling the outcome of their behavior. To make this clear, imagine two worlds, W1 and W2. In W1 the processes in the gunman’s brain end up sufficiently motivated to shoot, and in W2, the opposite happens. One goes to jail and the other lives his life in peace, but chance is the decider. Essentially, the problem is that this case has inherited all of the problems of compatibilism, but contains some indeterminism sprinkled within the neural systems of persons.
The other option is agent causation, which is in contrast to the normal conception of causation as events causing other events, and asserts that sometimes substances have powers that cause events. These are sui generis causal exercises. I won’t go into detail, but this option is wanting in that it doesn’t match up with our best scientific findings about the nature of persons.
To summarize, according to the basic strategy people lack free will because the sort compatible with determinism doesn’t secure moral responsibility and the alternatives to this either don’t enhance control or are highly implausible. It’s important to remember not to straw man the arguments of the sophisticated free will skeptics. They still believe that people make choices and that these are an important and meaningful part of life. What they deny is that the causal nature of our choices is sufficiently structured to secure “basic desert.” Basic desert is the condition by which a person deserves praise, blame, or punishment in the strongest sense for particular actions, simply by virtue of being an agent who freely made the decision to act. So, being disgusted or resentful of others are unjustifiable attitudes because the attitudes assume a notion of control which is lacking persons. The arguments for and against any particular pro-free will position are much more complicated than described here, but the structure is basically the same. Personally, I’m still undecided. I’d wager that we probably don’t have enough control to justify our contemporary criminal justice system and the relevant moral attitudes; but a reformed responsibility practice remains a live and under-appreciated option.