Men are mistaken in thinking themselves free; their opinion is made up of consciousness of their own actions, and ignorance of the causes by which they are conditioned. Their idea of freedom, therefore, is simply their ignorance of any cause of their actions. As for their saying that human action depends on the will, this is a mere phrase without any idea to correspond thereto. What the will is, and how it moves the body, none of them know; those who boast of such knowledge, and feign dwellings and habitations for the soul, are wont to provoke either laughter or disgust.

—Baruch Spinoza, Ethics

Few things can make you more skeptical about free will than studying anthropology. For me, this had three components.

The first was cultural. I read about the different customs, rituals, religions, arts, superstitions, and worldviews that have existed around the world. Many “facts” that I assumed were universal, obvious, or unquestionable were shown to be pure prejudice. And many behaviors that I assumed to be “natural” were shown to be products of the cultural environment.

It is unsettling, but nonetheless valuable, to consider all the things you do just because that’s what your neighbors, family, and friends do. These include not only superficial habits, but our most basic opinions and values. Our culture is not like a jacket that we put on when we go out into the world; culture is not a superficial layer on our deeper selves. Rather, culture penetrates to the very core of our beings, shaping our most intimate thoughts and sensations.

The next influence was primatology, the study of primate behavior. This came to me most memorably in the books of Jane Goodall, about the chimpanzees she studied. Chimpanzees are our closest relatives. They are recognizably animals and yet so strangely human. They get jealous, become infatuated, bicker, fight, make up, and joke around. They make tools and solve puzzles.

I remember the story of a small chimp who, while walking through the forest with his group, saw a banana out of the corner of his eye. The rest of his group didn’t notice it; and this chimp knew that the bigger ones would take the banana away if they saw him eating it. So he ran off in another direction, causing everyone to follow him, and then secretly snuck back to get the banana. If that’s not human, I don’t know what is.

Last was the study of human evolution. This also involves the study of archaeology: the material culture that hominins have left behind. I held reproductions of the skulls of human ancestors, and examples of the stone tools made by our smaller-brained predecessors. I saw how the tools became more advanced as the brain size increased. Crude choppers became the beautiful hand axes of the homo erectus, and these large axes became refined into serrated blades and arrow heads by later species. Finally our species began showing evidence of symbolic thinking: burying people, crafting statues, painting caves, carving flutes, and almost definitely using language.

After seeing the obvious influence of evolution on our capacities and tendencies, after learning about the striking similarities between us and our ape cousins, and after witnessing the pervasive effects of culture upon behavior, my belief in free will was in tatters. True, even if we take all these evolutionary and cultural factors into account, we can’t predict the exact moment when I’m going to scratch my nose. But neither can we predict where a fly will land, or which patch of skin a mosquito will bite. Nobody thinks flies or mosquitoes have free will, so why us?

I normally understand “free will” to mean the ability of an organism to fully determine its own actions. In other words, a free organism is one whose actions cannot be predicted or explained by pointing to anything outside, including genes or upbringing. Not DNA, nor culture, nor childhood experiences would be enough to fully explain a free individual’s behavior. A free action is, in principle, unpredictable; and thus the free agent is morally responsible for his actions.

I do not believe in this type of freedom, and I have not for a long time. For my part, I think Spinoza is exactly right: “free will” is just a name for our ignorance of the causes of our own behavior. If we knew these causes, our actions could be predicted like any other natural phenomenon, and “freedom” would disappear.

This ignorance is not difficult to explain. Human behavior is the product, first, of our environment, which is infinitely varied and constantly changing; and, second, of the human brain, one of the most complex things in the universe. Because of the amount and complexity of the data, along with our lack of understanding, we can’t even come close to making predictions on the scale of individual human actions, like scratching one’s nose. But we can’t conclude from our inability that our actions are thus “free,” anymore that we can conclude from our inability to predict where a fly will land that flies possess a mystical “freedom.”

Kurt Vonnegut made this point, with much more wit, in Slaughterhouse Five. His Tralfamadorians, who can see in the time dimension as well as space dimensions, already know everything that will happen. Thus they have no concept of freedom, and find it puzzling that humans do: “I’ve visited thirty-one inhabited planets in the universe, and I have studied reports on one hundred more. Only on Earth is there any talk of free will.”

To me it seems manifest that the traditional definition of freedom has been thoroughly discredited by what we know about the natural and cultural world. Humans are made of matter obeying physical laws, shaped by evolution, subject to genetic influence, and responsive to the cultural environment. The mind is not a mysterious metaphysical substance, but a product of the human brain; thus the mind and its behavior, like the brain, can be understood scientifically, just like any other animal’s.

All this being said, there are nevertheless ways to redefine free will so that it is compatible with what we know about physics, biology, anthropology, and psychology.

Perhaps free will is simply the inability of a thinking organism to predict what it is about to do? Every person has, at one time or another, been surprised by their own actions. This is because, as the philosopher Gilbert Ryle explained, “A prediction of a deed or a thought is a higher order operation, the performance of which cannot be among the things considered in making the prediction.” That is to say that it is logically impossible to predict how the act of predicting an action will alter the action, because the prediction itself cannot factor into the prediction (you can try to predict how you will predict, but this leads to an infinite regress).

Or perhaps free will is a condition caused by our ignorance of the future? After all, difficult decisions are difficult because we can’t be sure what will happen or how we’ll react. Deciding between two job offers, for example, is only difficult because we can’t be sure which one we’ll like more. If we could be sure—and I mean absolutely sure—which job would make us happier, then there wouldn’t be a decision at all; we would simply take the better job without a dilemma even occurring to us. In this way, our freedom is as much a product of our ignorance of the future as it is our ignorance of the causes of our actions.

What sets humans apart from other animals is not our freedom per se, but our behavioral flexibility. Humans are able to continually adapt to new environments, and to learn new habits, techniques, and concepts throughout their lives. This ability to adapt and to learn, which serves us so well, is not freedom so much as slavery to a different master: our environment. Our genes do not instill in us a specific behavioral pattern, as in ants, but give us the capability to develop many different behavioral patterns in response to our cultural and climatic surroundings. But is it any more “noble” or “free” for our behavior to be determined by social and environmental pressure rather than from genetic predestination?

Probably the best practical definition of freedom I can come up with is this: Humans are free because we are able to alter our behavior based on anticipated consequences. This is what makes morality possible: we can influence people’s behavior by telling them what will happen if they don’t follow the rules. What is more, people can understand that they have more to gain by playing along and helping their neighbors than by acting impulsively and at the expense of their neighbors. Thus our intelligence, by allowing us to understand the consequences of our actions, gives us the ability to be more intelligently selfish: we can weigh long-term benefits with short-term pleasures.

Freedom is, of course, a fundamental concept in our political philosophy. So if we choose to stop believe in freedom as traditionally defined, how are we to proceed? Here is my answer.

The important distinction to be made in political philosophy, regarding freedom, is what separates freedom from coercion. The difference between freedom and coercion is not that one is self-caused and the other caused by the outside—since even the freest person imaginable has been profoundly shaped by their environment, and is making decisions in response to their environment. Rather, there are two important differences: coercion implies force (or the threat of force) while freedom doesn’t; and “free” actions usually benefit the acting individual, while “coerced” actions usually benefit an outside party at the expense of the acting individual.

The difference thus has nothing to do with freedom as such (freedom from environmental influences), but is determined by the type of environmental influence (violent or non-violent), and by the party (actor or not) that receives the benefits. (Even though an altruistic act benefits a party besides the actor, it is not a coerced act because, first, it’s not motivated by threat of violence, and, second, because altruistic acts usually benefit the actor in some way, either socially or psychologically.)

I find that some people become horrified when I tell them about my rejection of freedom. For my part, I find that my disbelief in freedom has made me more tolerant. When I consider that people are products of their environment and their genes, I stop judging and blaming them. I know that, ultimately, they are not responsible for who they are. In a profound sense, they can’t help it. We are each born with certain desires, and throughout our lives other desires are instilled into us. Our behavior is the end product of an internal battle of competing desires.

If you think that morality is impossible with this worldview, I beg you to read Spinoza’s Ethics. You will find that, not only is morality possible, but it is necessary, logical, and beautiful.