If we are prepared to take the life of another being merely in order to satisfy our taste for a particular type of food, then that being is no more than a means to our end.

There is no humane slaughter requirement for wild fish caught and killed at sea, nor, in most places, for farmed fish.

Personal purity isn’t really the issue. Not supporting animal abuse – and persuading others not to support it – is.

If governments did not mislead their citizens so often, there would be less need for secrecy, and if leaders knew they could not rely on keeping the public in the dark about what they are doing, they would have a powerful incentive to behave better.

I would like us to think about it more explicitly, and not take our intuitions as the given of ethics, but rather to reflect on it, and be more open about the fact that something is an ethical issues and think what we ought to do about it.

Of those who die from avoidable, poverty-related causes, nearly 10 million, according to UNICEF, are children under five. They die from diseases such as measles, diarrhoea, and malaria that are easy and inexpensive to treat or prevent.

Knowing that we can control our own behaviour makes it more likely that we will.