The irrationality of disgust suggests it is unreliable as a source of moral insight. There may be good arguments against gay marriage, partial-birth abortions and human cloning, but the fact that some people find such acts to be disgusting should carry no weight.

It's hard to pull apart empathy from compassion. What is really clear is that we innately care for other people at least to some extent.

I have two teenage sons, and they're both surviving, thriving, and having a great time, and they're always on social media.

We don't just respond to things as we see them, or feel them, or hear them. Rather, our response is conditioned on our beliefs, about what they really are, what they came from, what they're made of, what their hidden nature is.

This enthusiasm [for empathy] may be misplaced. Empathy has some unfortunate features – it is parochial, narrow-minded and innumerate. We’re often at our best when we’re smart enough not to rely on it.

The effects of Twitter and Facebook and all those things on people's psychologies is a really interesting question to which nobody knows the answer.

My younger son told me nobody uses email anymore. I'm this old fogie with my email. I don't know what I'm supposed to communicate with now - SnapChat?