Why do we punish criminals? Is it to keep society safe, to exact revenge, to set an example or to teach the criminal a lesson? Which of these motivations would lead to the most just society?

Good questions. The answer to your first question is, basically, all of the things you list in your second question, plus some. The justifications for criminal punishment are typically divided (oversimplistically) into two theories: "backward-looking" retribution and "forward-looking" consequentialism. The forward-looking theories (often associated with utilitarian ethics) focus on the future benefits of punishing criminals: (1) deterring the criminal from further crime, (2) deterring others from carrying out crimes, and perhaps also (3) rehabilitating the criminal and (4) restitution of the victims. The backward-looking theories (often associated with Kantian ethics) focus on what happened in the past--the crime committed, the harm done, the guilt of the criminal--and aim to punish the criminal as much as he or she deserves it, which may include making the criminal suffer an appropriate amount, but perhaps also forcing him or her to make up for the crime with restitution. This...

In The Stone column on the New York Times Site, there is an article about the issue of moral responsibility, in light of the notion that we are what we are because of such factors as genetics, environment, or perhaps determinism and/or chance. In the end the author stoically concludes, that despite it all in some sense we can choose to take responsibility for our actions. While I respect the author's sense of duty, can we fairly extend that same responsibility to other people? For example, could there still be any defense of punishment that isn't consequentalist. For that matter how can any nonconsequentialist ethical theory hold up against this argument?

Given your question, you may be interested in a discussion of Strawson's NYTimes article at the free will/moral responsibility blog, Flickers of Freedom, here . There's also a discussion on retribution and punishment (and psychopaths) at the blog here . You'll see in these discussions that there are plenty of philosophers (called compatibilists) who think that free will and moral responsibility are possible even if determinism is true, and who reject Strawson's argument against the possibility of freedom and responsibility. These compatibilists will generally say that retributive punishment is justified, though they might also think that punishing (or treating) criminals for consequentialist reasons (such as deterrence and rehabilitation) is also important. My own view is that we can have free will and moral responsibility (determinism is irrelevant to this issue), but that we have less than we think (because the sciences of the mind are showing that we have less self-knowledge and...

Suppose a man commits murder and is then promptly involved in a car crash that leads to complete loss of all his memories prior to the car crash. The police have indisputable proof that the man did indeed commit the murder. Should they prosecute? If you conclude that they should because in some sense he's physically the same person what if a murderer somehow makes a copy of themselves and then commits suicide, should the copy be prosecuted? If you conclude that they shouldn't be prosecuted because the person after the accident is a different person from before the accident what if there's indisputable evidence that all of their memories will return in 5 years? 5 weeks? 5 days? To my mind the person after the accident is a different person from the one who committed the murder and should therefore not be prosecuted. If the memories return then they should be prosecuted but we shouldn't punish them for a crime "they" didn't commit. But I am unsure as to how much of their memories need to return before...

Wow, you have come up with a case I love to use in my philosophy of mind to connect issues of personal identity to moral responsibility and "moral luck." I have students read the Oliver Sacks' case of Donald ("Murder" in The Man Who Mistook His Wife for a Hat ). Donald took and, while high, killed his girlfriend. He had no memory of the incident (assume this is true for now) and was found not guilty by reason of (temporary) insanity. A few years later he was hit by a car and suddenly (re)remembered the gruesome murder (offering details only the killer could know). The case raises lots of questions: Is Donald on PCP (DPCP) the same person as Donald before (DBefore)? And is Donald at trial and the next few years (DTrial) the same as DPCP ? And is Donald after recovering his memories from the accident (DAfter) the same as ... and DTrial and DBefore?? And beyond these questions about personal identity, there's the question of moral luck: assuming that Donald before (DBefore) had no...