I think that a lot of social movements, political movements, powerful ones - certainly they form, collectively, an idea of the truth which becomes hard to question. It becomes a dogma, and from the inside it starts to look like common sense.

The capacity to make free choices is not something we either have entirely or not at all. Rather, choices become freer the more they are the result of our own capacity to reflect on and assess facts and arguments.

Philosophy is at its most engaged when it is impure. What is being recovered from the Ancient Greek model is not some lost idea of philosophy's pure essence, but the idea that philosophy is mixed up with everything else.

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.

If there is an art of living, it is not something that can be taught timelessly. We have lessons to learn from Aristotle et al, for sure, but not if we simply uproot them from their epoch and stamp them into 21st-century soil.

Trade has played a vital role in the social evolution of humankind. It allowed people to specialise, which raises both skill levels and efficiency. It brought people from different lands together, co-operating rather than competing over resources.

The border between the natural and the supernatural, religion and philosophy, may not always be clear. But there are lines and we should know and accept which side of it we are on.