Here’s an ancient question, asked again by almost every generation. What is a person’s character? Is it something they have — a kind of inner core that’s revealed, situation after situation, in how they respond? Or is it something they do — a set of patterns built up over time, through repeated action, that can be strengthened or weakened like a muscle?
The answer has practical consequences. If character is a fixed trait you either have or lack, then the honest path is to discover yours and live accordingly — accept the limits of who you are, and stop pretending you can be other than that. If character is built through practice, the honest path is different — notice what kind of person you’re becoming through your repeated actions, and act to become someone you’d want to be.
These two framings have been in conversation for two and a half thousand years. The research of the last few decades has, on balance, pulled sharply toward one of them.
Aristotle’s proposal
The first systematic answer to this question, in the Western tradition, came from the Greek philosopher Aristotle, writing in the fourth century BCE. His Nicomachean Ethics makes a specific and quite radical argument: virtues — the traits that make up good character — are habits. They aren’t natural endowments you’re born with. They aren’t feelings you have or don’t. They’re dispositions built up through repeated action.
“We become builders by building,” Aristotle wrote, “and we become lyre-players by playing the lyre. In the same way, we become just by doing just actions, temperate by doing temperate actions, brave by doing brave actions.”
This is a strange claim if you’ve never considered it. It says that the way to become courageous is not to discover whether you have courage inside you. It’s to repeatedly perform acts of courage, even when they feel hard, until courage becomes a habitual response. The same for honesty, generosity, patience, and the rest. Character is built by practice — which means character is something you do to yourself, through repeated choices, across years.
Aristotle’s framework was coherent, influential, and — importantly for our purposes — largely forgotten or marginalised during most of the last century of psychology. Much of modern psychology, particularly the traditions influenced by Freud and his successors, treated character as something deeper than habit — an unconscious structure, a personality type, a pattern of attachments laid down in early life and largely fixed thereafter.
James, and the bridge to modern science
The American psychologist and philosopher William James, writing in 1890, wrote a chapter that would bridge the ancient framing to the modern one. Titled simply Habit, it appears in his foundational textbook The Principles of Psychology, and it’s probably the most-quoted single chapter in the history of American psychology.
James argued, much like Aristotle, that character is essentially a bundle of habits. Every time you act in a certain way, you make that action slightly easier to perform next time. Every time you refrain, you make it slightly harder. Over years, these tiny increments accumulate into settled patterns of behaviour that an outside observer would correctly describe as character. A person who has, across a decade, repeatedly chosen honesty in small moments has built a habit of honesty that will, in the eleventh year, make honesty their default response even when it costs them something. A person who has repeatedly cut corners has built a different habit, equally durable.
James’s most famous passage from the chapter is worth quoting in full, because it has a specific practical edge:
“Could the young but realize how soon they will become mere walking bundles of habits, they would give more heed to their conduct while in the plastic state. We are spinning our own fates, good or evil, and never to be undone. Every smallest stroke of virtue or of vice leaves its never-so-little scar.”
The claim is sobering, and it holds up reasonably well against a hundred and thirty years of subsequent research. James’s broader point — that the habits of your twenties substantially shape the character of your forties — has become, if anything, more strongly supported as longitudinal studies have tracked how specific early patterns predict later adult life.
The contemporary habit science
Modern psychology has developed much of the technical detail James was groping toward. The most accessible synthesis for a general audience came from the journalist Charles Duhigg, whose 2012 book The Power of Habit drew on research from multiple labs to describe how habits actually form and how they can be changed.
The core finding, drawn especially from the work of neuroscientists including Ann Graybiel at MIT, is that habits form when a repeated action sequence becomes encoded in a specific brain region — the basal ganglia — that handles automatic behavioural patterns. Once a behaviour is habitual, the prefrontal cortex (responsible for deliberate choice) becomes less involved. The action runs on autopilot, triggered by a cue, producing a reward, with minimal conscious engagement.
This has practical implications that Aristotle couldn’t have known but that turn out to support his framework. Character, in this model, isn’t primarily about what you decide to do moment by moment — it’s about what your basal ganglia will produce automatically in response to ordinary cues. By the time you need to be honest, it’s too late to decide to be honest. The decision was made in the hundred previous situations that built whatever habit your basal ganglia has now. The conscious moral decision is almost always a confirmation of what the habits have already produced.
This is both encouraging and uncomfortable. Encouraging because it means character is genuinely buildable — the ancient Aristotelian insight was largely right, and modern neuroscience explains why. Uncomfortable because it means character is hard to change quickly. You can’t decide, at thirty-five, to become a person with different habits by an act of will. You have to actually build the habits, which takes the time building habits takes.
The cognitive-behavioural tradition
A third contributing tradition comes from the cognitive-behavioural therapy movement, founded in the 1960s by the American psychiatrists Aaron Beck and Albert Ellis. CBT’s core insight was that mental patterns — the recurring thoughts, interpretations and emotional responses that characterise a person’s mental life — are learnable and changeable, not fixed features of personality.
Applied to character, this framework extends the Aristotelian model. What you think, when you face a difficult situation, is partly a matter of mental habit. Someone who has repeatedly interpreted others’ behaviour charitably has built a cognitive habit of charitable interpretation, which will produce different responses in a hundred small future interactions than someone who has repeatedly interpreted others’ behaviour suspiciously. The mental habit, like the behavioural habit, is real, durable, and cultivable.
This has therapeutic implications. CBT has reasonably strong evidence for helping people with depression, anxiety, and related conditions. Part of what it’s doing, in the Aristotelian frame, is retraining mental habits — helping someone who has developed a habit of catastrophic thinking to build, through practice, a habit of more proportionate interpretation. The practice takes weeks or months. It’s not a quick fix. But it produces, over time, real changes in the automatic mental responses that had previously seemed fixed.
The situationist critique
Before accepting the Aristotelian framework wholesale, it’s necessary to take seriously a significant counter-tradition that emerged in the late twentieth century, pointing in an almost opposite direction.
The philosophers Gilbert Harman and John Doris, drawing on classic social-psychology experiments, argued that traditional virtue ethics — including the Aristotelian framework — rests on an empirically questionable assumption. The assumption is that people have stable character traits that produce consistent behaviour across situations. The research, they argued, suggests otherwise.
The central evidence came from experiments showing surprisingly large situational effects on behaviour. Stanley Milgram’s obedience research found that ordinary people, when instructed by authority figures, would administer what they believed were dangerous electric shocks to strangers. Philip Zimbardo’s Stanford Prison Experiment (the methodological problems with which we’ll discuss elsewhere, but which is still cited in this context) purported to show that ordinary students, assigned to the role of prison guards, would quickly exhibit cruel behaviour. Less dramatic but perhaps more telling studies, like John Darley and Daniel Batson’s Good Samaritan study, showed that seminary students who had just been asked to think about the parable of the Good Samaritan were significantly less likely to help a stranger in apparent distress if they were in a hurry than if they had time — the situational variable dwarfed any dispositional difference in character.
Harman and Doris’s conclusion, based on this body of evidence, was that character traits in the traditional sense may not really exist. What we think of as a person’s character is substantially an illusion produced by the stable situations we usually observe them in. Put them in unfamiliar situations, and the apparent character evaporates.
This is a serious challenge to the Aristotelian framework, and it deserves to be held honestly. If character is mostly a function of the situation you’re in, then the practice of building character through repeated virtuous action is partly misguided — you’re building up a trait that won’t transfer when the situations change.
The synthesis worth holding
What most thoughtful contemporary philosophers and psychologists have concluded is somewhere between the full Aristotelian and the full situationist views. The philosopher Christian Miller, in his book The Character Gap, makes a reasonable case for the synthesis.
Character traits, Miller argues, are real but weaker and less stable than traditional virtue ethics assumed. Most people don’t have strong virtues in the Aristotelian sense — fully reliable dispositions that produce the virtuous action regardless of situation. What most people have are mixed traits, partial habits, dispositions that work in familiar contexts but fail in unfamiliar ones. The situationist critique was right that character isn’t as robust as philosophers hoped. The Aristotelian tradition was right that character is nevertheless real and cultivable.
The practical implication is twofold. First, you can genuinely build character through practice — the research supports this. Second, you shouldn’t expect your character, once built, to be a reliable guarantor of good behaviour in radically unfamiliar situations. Character is more like a trellis you’ve built for yourself than a fortress. It supports the kinds of growth it was built to support. Put it under different conditions, and it may bend in ways you didn’t predict.
What to do with this
For an individual trying to become a better version of themselves, the synthesis is actually more useful than either pure view.
Practice matters, but practice in context. The character you build through daily actions in familiar situations will work reasonably well in similar future situations. It may not transfer to radically different ones. This isn’t an excuse to stop practising — it’s a reason to practise across a range of contexts rather than only in the comfortable ones.
The small actions are the work. The hundred small moments a day when you choose to listen patiently, tell the truth, do a hard thing rather than avoid it — these are not rehearsals for the important future moments when character will be tested. They are the work of character itself. There is no other work. The person you are at sixty will be almost entirely the product of the countless small choices you made between now and then.
Watch your situational conditions. If you’ve been surprised by your own behaviour in a specific situation — behaving worse, or better, than you’d have expected — the situationist tradition suggests paying attention to what in the situation produced the effect. It’s information about conditions, not just about you.
Accept slow change. You can’t decide in a day to be a different person. You can decide in a day to start building a habit, and continue the practice for the years it takes. The disappointment of not changing faster is usually a disappointment with a realistic timeline rather than with any failure of effort.
The question that remains
The oldest question about character — is it discovered or built? — turns out, at least partially, to have an answer. It’s built. Not quickly, not completely, not with certainty. But more than old-fashioned personality theories implied, and perhaps more than the self-help industry’s quick-fix framings imply in the other direction. Character is the long accumulation of small actions. Nobody else can do the building for you. Nothing can substitute for the practice.
The question worth carrying:
The person you’ll be in ten years — what small habits, started today, would be the building materials they’d thank you for laying down?
Key research referenced: Aristotle, Nicomachean Ethics (4th century BCE); William James, The Principles of Psychology (1890), chapter on habit; Charles Duhigg, The Power of Habit (2012); Ann Graybiel’s neuroscience of habit formation; Aaron Beck and Albert Ellis on cognitive-behavioural approaches; John Doris, Lack of Character (2002) and Gilbert Harman on situationism; Christian Miller, The Character Gap (2017).