Both Proust and Joyce record the ways in which human perspectives can be transformed. In Portrait, Stephen Dedalus is constantly undergoing epiphanies, but their effects are transitory: the new synthetic complex quickly falls apart. Proust's characters, by contrast, often achieve lasting changes of perspective.

After two years of undergraduate study, it was clear that I was bored by the regime of problem-solving required by the Cambridge mathematical tripos. A very sensitive mathematics don recommended that I talk to the historian of astronomy, Michael Hoskin, and the conversation led me to enroll in the History and Philosophy of Science for my final undergraduate year.

The result can be quite new - perhaps a tendency to judge that something we've never conceived of is possible, or to feel sympathy for a trait or a type of person whom we've regarded with indifference or even hostility.

There are actually two separate issues here. The first is whether (as ancient philosophers and Nietzsche assume) only the privileged elite can live a worthwhile life. The second is whether it's possible to fulfill the roles of both serious artist and upstanding citizen. It seems to me that philosophy can dissect both questions, by delineating clearly the anatomy of the good life and the structural conditions of the roles.

Experiments work when, and only when, they call into action cognitive capacities that might reliably deliver the conclusions drawn.

The point of philosophy, as I see it, is to change thinking, and thereby to change the conversation.

The hardest problem of all is to appreciate the facts that the poor nations are - quite reasonably - not going to forgo their development, and that they can only afford to develop by consuming fossil fuels.