The newspapers do little better. Their coverage of nonhuman animals is dominated by "human interest" events like the birth of a baby gorilla at the zoo, or by threats to endangered species; but developments in farming techniques that deprive millions of animals of freedom of movement go unreported.

When fish experience something that would cause other animals physical pain, they behave in ways suggestive of pain, and the change in behaviour may last several hours.

What is there about the notion of a person, at law, that makes every living member of the species Homo sapiens a person, irrespective of their mental capacities, but excludes every nonhuman animal - again, irrespective of their mental capacities?

Each of us spends money on things that we do not really need. You could take the money you're spending on those unnecessary things and give it to this organization the Against Malaria Foundation which would take the money you had given and use it to buy nets to protect children. And we know reliably that if we provide nets, they're used, and they reduce the number of children dying from malaria. Fortunately more and more people are understanding this idea, and the result is a growing movement effective altruism.

I don't see how anyone could really think that if you have a choice between saving the life of one person and saving the lives of a million people, to say - well, I've saved the one - can you really take that seriously? I can't.

The animal liberation movement is saying that where animals and humans have similar interests - we might take the interest in avoiding physical pain as an example, for it is an interest that humans clearly share with other animals - those interests are to be counted equally, with no automatic discount just because one of the beings is not human.

So far as this argument is concerned nonhuman animals and infants and retarded humans are in the same category; and if we use this argument to justify experiments on nonhuman animals we have to ask ourselves whether we are also prepared to allow experiments on human infants and retarded adults; and if we make a distinction between animals and these humans, on what basis can we do it, other than a bare-faced - and morally indefensible - preference for members of our own species?