o the same way.
Those close to people who seem greatly changed by dementia sometimes say such things as “He isn’t the man I married”, or “She is a different person now”. At one level we all understand what such comments mean. But at another level they raise philosophical problems about the boundaries of personal identity.
Those who make the comments may not be clear how literally they mean them. If they are meant literally, some philosophers will accept them and others will reject them. Those who see personal identity as a matter of physical continuity will think in terms of the same person having a changed psychology. Those who take a more psychological view of personal identity will be more willing to see discontinuities of memory or of personality as raising doubts about the person being the same. Others will say that the earlier person may survive to some degree. Here these issues will be sidestepped. I will talk in terms of the same person having a changed character and personality, but the discussion could be translated without loss into the language of the old and the new person, or into the language of earlier and later selves.
A. Aristotelian Common Sense.
How does the thought that this person has changed so radically bear on his or her responsibility for the actions shaped by the new personality?
One possible answer is that it makes no difference at all. In other contexts, people often change radically. People have religious conversions. They change partners and jobs and they emigrate. They take up drugs or enter convents. Any of these upheavals may change character and personality sharply. But the immigrant or the nun are still held responsible for what they do. The new actions flow from the new personality, and it is still appropriate to evaluate the person on the basis of them. The novice nun’s piety (or the new immigrant’s patriotism) is not less relevant to our picture of them because they are newly acquired. So why should the aggression of the person with dementia or a brain tumour be different?
A reply to this question could appeal to the way in which, as Nietzsche saw, we at least partly create ourselves. Nietzsche’s version of self-creation was a highly self-conscious one, making people like architects or landscape gardeners of their own character and personality. He was right that many of us do care about the sort of person we are, and do to some extent try to grow in one direction rather than another. But for most people self-creation is less dramatic than in Nietzsche’s picture: more a matter of trying to be the sort of person who answers letters, or who gives up a job in public relations because you don’t want to be the kind of person you see you are becoming. And less dramatic still is the often completely unconscious self-creation that comes about when repeated actions become character-shaping habits.
Aristotle took the view that our character is something we are responsible for, because it results from our own freely chosen actions. Pointing out that we punish people who, through carelessness, are ignorant of things they should know, he says that we assume that they have the power to take care. He then considers the objection that someone may be a careless kind of person. He replies that becoming such a person is their own fault: “they are themselves by their slack lives responsible for becoming men of that kind, and men make themselves responsible for being unjust or self-indulgent, in the one case by cheating and in the other by spending their time in drinking-bouts and the like; for it is activities exercised on particular objects that make the corresponding character.” He accepts that, once we have a certain character, we may be unable to change it at will, but says that it was still pour own fault that we acquired it. (3.)
This robustly “common sense” Aristotelian view is broadly presupposed by most legal systems and by the everyday morality of praise and blame. There is the presumption that actions are voluntary unless there is some special reason to think that they are not, together with 