A lot of religious belief - even the majority - involves making factual claims about the world which do come into conflict with science and history. For Christians, a test of this is the Empty Tomb. I ask Christians: 'are you saying that it does not matter - as a matter of fact - whether or not Christ's tomb was empty and that he was resurrected?' At that point, I find that, to a lot of them, it really does matter, despite all the fine talk about not wanting to confuse science and history with religion.

Progress is more of a challenge for the cynic but also more important and urgent, since for the optimist things aren't that bad and are bound to get better anyway.

Rules matter, and to be rules they need to be universal in form: always do this, never do that. But it is foolish to rule out in advance the possibility that an occasion might arise when normal rules just don't apply. Rules are not there to be broken, but sometimes break them we must.

The very act of questioning whether you exist proves you do, because you must be there for the doubt to be entertained in the first place.

To become a stoic is to endorse the truthfulness of its world view and accept its prescription for how you ought to live, not just to like how it makes you feel.

Whatever the truth is about the extent to which truth is respected in the future, it is going to depend partly on what we do. More important than making predictions is doing things which help bring about this respect.

For most people their ideal life involves an intimate relationship with another person; one which often has a sexual basis. But there's no logic about it; why shouldn't people choose to live together with someone they just like? 'Of course' if we were too unquestioning about it, and we said 'well, that person has got to be someone of the opposite sex, and it's got to be for life, and divorce is terrible', then we're stuck. But if you don't recognize the importance that kind of bond has for human beings - you can't really understand what is needed to live a good life.