conclude, what Thomas Mann really wanted was a limited physical relationship with beautiful young men: the opportunity to gaze at them, an occasional touch, a restrained kiss. That isn't a surrogate for what he'd like to have if he were somehow free from social constraints. It's what the young Platen wanted, it's what he wanted - and it's what his Aschenbach wants.

There's a disciplined erotic component to it, so that the height of sexual contact is the embrace, the modest touch, a relatively chaste kiss. An important passage from the surviving 1942 diary (one I quote in the book) relates this mode of sexual expression to his own life. Mann had returned to his diary for 1927 (one of those he burned) and to his parting from the young man, Klaus Heuser, whom the family had met on holiday and invited to Munich.

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.

In my current work on global warming, I argue that the only apparent solution to the deep problem of climate change would require very large transfers of wealth from rich nations to poor nations, so that the entire world can make the transition to renewable forms of energy as fast as possible.

So this is my attempt to give a preliminary - probably far too crude - account of how philosophy by showing can really teach us. The attempts we make to work through problems by reasoning always presuppose starting points, and even the most self-critical philosophers adopt some of those starting points simply by picking them up from the social environments in which they grow up.

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.

When I try to outline the history of ethical life, it's sometimes possible to find evidence for a hypothesis about how important transitions actually went. Often, however, that isn't so. There are many facts about human life in the Paleolithic we're never likely to know.