On November 27, 1978, Dan White, a former firefighter and policeman, assassinated the Mayor, George Moscone, and a supervisor, Harvey Milk, of San Francisco. His guilt was not denied. But his lawyer argued that White had a diminished capacity for rational thought, and therefore couldn’t be guilty; he was suffering from deep depression, and incapable of premeditating murder. As a symptom of his wretched mental state, his lawyer pointed out that he was eating mostly sugary foods, including Twinkies (the ‘golden sponge cake with a creamy filling’, according to its maker Hostess Brands). He didn’t claim that Twinkies caused his murderous outburst, but of course, his case instantly became known as the ‘Twinkie Defense’, according to which his crime was the product of his depressed mental state.

Our systems of retributive justice, which punishes wrongdoers, would have a problem accepting that defense. But it’s the product of a line of reasoning being promoted ever more forcefully by some philosophers, scientists, and legal scholars. Our decisions, they argue, are innately determined. This together with the effects of genetics, the environment, and life experience, means we have no free will. If so, our misbehavior is beyond our control. Dan White’s case is related to that of the ‘Westside Story’ character Riff, “I’m depraved on account of I’m deprived.”

I have little expertise in philosophy. I struggled to get through a survey course in first year university. Of course, like most people, I have an opinion. But I’ll turn the discussion about free will, and whether or not we have it, over to people who spend a lot of time thinking and writing about it. First the free will deniers.

We have no free will

That heading sums up the position of a large number of deep thinkers. It originates from the worldview created by the French physicist Laplace, where everything happens because of a cause. If we know the angle at which the cue ball hits the black 8, we can predict the directions of both balls after contact. With knowledge about the friction of the balls travelling over the felt, we can predict where they will come to rest. This is called determinism.

In determinism, once the cause happens, the action follows. But that cause was itself an action that was the product of an earlier cause. A series of causes and effects determines everything that happens in the physical universe, and since our neurobiology, the nerves and the neurotransmitters and all the other bits of our mental machinery, are all physical entities, they are subject to determinism, and we do not have free will. What we have is a brain that is controlled by previous causes and actions. That chain of causes and actions goes all the way back to . . . the Big Bang, 13 billion years ago? The view that determinism controls all of our actions, that we have no free will, is called ‘classical determinism’.

The central argument for classical determinism being an argument against free will is that our brains do the thinking, and our brains are physical and chemical structures whose components obey deterministic rules. We can’t imagine a mental process, say making a free choice, without imagining a physical system, i.e. the brain, responsible for it. Ergo, the decision-making process must be deterministic.

Classical determinism is based on Newtonian physics. Experiments in the 1980s are said to support its role in decision-making. In those experiments, subjects were asked to flex their wrists whenever they felt like it. Electronic brain activity was monitored, and it showed that about a half second before people flexed their wrists there was electrical activity in the brain. But they only became aware that they were about to flex their wrists about a quarter second before the event: the brain ‘knew’ before they became conscious of their intent. Critics of that line of reasoning point out that we don’t know what the early brain activity was about — it may have been an indication that there was an intent to make a decision, which was initiated by an earlier, conscious decision.

A more recent study found that neural activity which predicted the nature of a mental decision (addition vs subtraction of two numbers) occurred four seconds before subjects of the study were aware that they had made a choice. Again, that doesn’t prove that their decision was pre-ordained, only that the brain works in a certain way. The early brain activity may have reflected an unconscious bias — the predictive value of the early signals was barely significant — it was better than random chance by about 10%. Furthermore, as pointed out by MIT physicist Eddy Nahmias (1), we change our minds much more quickly than suggested by the four second gap. If we didn’t, we’d all be dead in car accidents.

The idea that we have no free will is scary

That idea that we have no free will sounds counterintuitive to most people, going against common sense. But its supporters are no mean bunch. One of the most heavily read public intellectuals of our time, the American philosopher and neurobiologist Sam Harris, has published a short book ‘Free Will’ (Free Press), which argues that free will is an illusion (2). Based on the neural imaging studies mentioned above, Harris concludes that we are ‘biochemical puppets’. Another well-received philosopher, Robert Sapolsky, recently published a similar thesis in his book ‘Determined. A Science of Life Without Free Will’ (Penguin Press) (3).

A life without free will scares many people, for good reason. If we have no free will, then we are not responsible for our actions, and that would include the most heinous crimes, such as the assassinations carried out by Dan White. Supporters of this idea are not silly: they argue that, instead of incarcerating criminals in often brutal prisons, we instead either try to change their behavior, or at least house them under more humane conditions, something like the more grown-up system followed in Norway. Incorrigible bad actors would have to be quarantined. Few people would argue that prison conditions shouldn’t be improved, especially here in North America. But the no-free-will idea is still uncomfortable for most people.

Also, having no free will deprives humans of agency: falling in love is just an outcome of our biology (sometimes that does seem to be what happens). Still, it means that there’s nothing heartwarming about loving, or sacrificing for, another human — it’s just clockwork.

Other theories that support a lack of free will

There are various lines of thought within the No Free Will philosophical world. One proposes that thoughts and actions are partly controlled by random events, probably happening in our brains. Mutations, or gamma rays from outer space come to mind. And if that’s true, if our actions and thoughts are in fact due to random events, then again, we have no control, and no free will.

Another aspect of behavior is that it is affected by genetics, and that is surely true. My post on the genetic separation of human-friendly from snarly foxes supports the important contribution of genetics to behavior for a group of foxes, and of course, we are foxy animals ourselves.

As for environmental effects on behavior, if a potential criminal is aware that the cops are hyper-vigilant in his part of town tonight, he may not knock over the convenience store he has had his eye on. Environmental cue, dude. More importantly, being brought up in a bad environment can lead to a greater likelihood that a person behaves badly later in life. The abused become abusers. Experience can influence our decisions, but having an influence, and completely negating free will, are not the same thing. The best way to imagine this, if you believe in free will, is that your range of choices may be shifted by other factors, so you may be more inclined to make one decision (say criminal behavior) than another (behaving lawfully) by a poor experience growing up.

All of these arguments, the dominance of determinism, the importance of random events, genetics, and environment, argue against the idea that we have free will. Is there an opposing argument? Indeed there is.

Is it really a deterministic universe?

Determinism, based on Newtonian physics, has brought us a long way. It’s the basis for almost everything we make or do. It results in cars that go fast, in drugs that cure disease, in weather predictions that help us prepare for storms (although in that case random events are also involved). One problem with the classical deterministic argument against free will is that we know that determinism is not the right description for everything that happens (4).

Newtonian physics, a guiding system for our civilization, predicts outcomes at a macroscopic level. But there’s a more modern theory for how things happen at a subatomic level, which is quantum mechanics (QM). In QM, outcomes are not predicted, only probabilities. Acting on a system can produce an unpredictable outcome. In the QM world, ‘shit happens’, and we can only predict the outcome for a large population of events. QM accurately describes the subatomic world, where Newtonian physics does not go. It’s not a wholly deterministic world out there, or in here.

The firing of the brain before a person is aware of a coming decision, as described by the experiments in the 1980s, is not considered a proof of lack of free will by Sapolsky himself (although Harris considers that it is). The manipulative effects of hormones, or cultural or moral values, or experience, are also not proof of a lack of free will, according to this champion of no free will. Basically, there isn’t scientific proof, because, according to Jennifer Rifkin, reviewing Sapolsky’s book in the New York Review of Books, the question of free will is not a scientific question, but a philosophical one (5).

It is known that formulating the intention of carrying out a task, what psychologists call ‘implementation intention’, increases the chances that we will achieve its goal. For example, a dieter who decides to avoid thinking about tempting foods is more likely to be successful in their dietary aims than a person who has not thought about that. That suggests that we can affect the outcome of our mental activity, i.e. that we have free will. Of course, a hard-core free will denier will say that even the decision to think about a problem was pre-determined.

A fundamental problem is that we don’t know how thoughts happen. The ‘thought-making’ mechanism is a mystery (like consciousness).

So, Do We Have Free Will?

Although the free will deniers seem quite sure of their position, I think it’s a question for which there is no scientific solution at present. You may think one way or the other — that we do, or we don’t have free will. Maybe you don’t have any choice?

The Twinkie defense isn’t one

Dan White’s lawyer proposed that he was unable to form the intent to murder by his mental state. This ‘Twinkie Defense’ didn’t convince the judge that he should find White innocent by reason of mental infirmity; the ‘Twinkie defense’ isn’t one. But the jury was probably influenced. They gave White only a 7-year jail sentence. The uproar that followed the jury decision resulted in abolition of the ‘diminished capacity’ criminal defense in California. White was out in 5 years and dead by suicide in 7.

The city supervisor White murdered, Harvey Milk, was the first openly gay man in San Francisco’s city government. His murder was made into the movie ‘Milk’, starring Sean Penn, in 2008. Penn won an Academy Award for his performance.

Sources cited

1. Eddy Nahmias, “Why We Have Free Will”, Scientific American Magazine Vol. 312 No. 1 (January 2015), p. 76
2. Sam Harris, “Free Will”, (Free Press), 2012.
3. Robert Sapolsky, “Determined. A Science of Life Without Free Will”, (Penguin Press), 2024.
4. Mark Balaguer, The MIT Press Reader, ‘Why the Classical Argument Against Free Will Is a Failure’, Jan. 27, 2022.
5. Jessica Rifkin, ‘Turtles All the Way Up’, New York Review of Books, Feb. 13, 2025.