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.

People do care where their food, or other goods, comes from, not merely if the price is right. And that means no business can afford to ignore the impacts their buying practices have on producers and on the perceptions and choices of consumers.

From time to time, it is worth wandering around the fuzzy border regions of what you do, if only to remind yourself that no human activity is an island.

Science works because the phenomenon being described can be relied on to remain the same. Even in quantum physics, where phenomena are changed by observation, the way in which observation interferes is regular and falls within a limited range of possibilities. Human culture, however, has the nasty habit of never staying the same for very long.

Yesterday's news feeds our fear that our neighbours are more likely than not to be bad eggs: benefit fraudsters, bogus asylum seekers, paedophiles or jihadist terrorists.

True respect means taking other people's beliefs seriously and assuming they are adult and intelligent enough to be able to cope with it if you tell them, clearly and civility, why you think they are totally, utterly and disastrously wrong.

People should not expect the state to protect them from fraudsters. If we do, we get into the habit of neglecting our own powers of intellectual discernment.