You should say things that are sensible, and you should be sceptical of views that say things that are very silly. But I have a few guidelines, and one of them is that you should try and speak sense. That’s what people call the epistemology of metaphysics, the theory of how you know things in metaphysics. It reappeared sometime in the 1960s or 70s and now it’s one of the dominant areas of philosophy and people are just doing metaphysics unashamedly.”Īnother thing lying behind your question is ‘How do you know which view is right?’ Supposing someone says ‘Nothing ever changes,’ and someone else says ‘Everything changes.’ This is one of the oldest questions in philosophy - going back to Heraclitus - and I don’t have an answer to that question. Science might start off with puzzles and mysteries, but you don’t investigate it by pulling the problem apart, you investigate it by having data and having theories. That’s very different from the way that you find things out in science. So I would say the way you find things out is by investigating the source of confusion and puzzle and mystery like that. I’m slightly more bulky and I’ve got less hair - how can I be identical to what I was? What’s wrong? How can the very same thing have changed any of its properties, if having the same properties is what makes you the same thing? But then you start thinking about what it is for something to be identical and you say ‘Things are identical when they have all their properties in common.’ Then you get into problems, because I don’t have all the properties that I had thirty years ago. To be one and the same thing - there’s only one of you and there’s only one of me, and thirty years ago there was only one of you and one of me.

Philosophers have thought of that in terms of identity. If you think of an object, the very, very same object - say a person - continuing to exist across time.

The way people encounter metaphysics is often through problems or paradoxes. How could you possibly discover anything like that? In metaphysics you ask ‘What is change? How is change possible?’ No science will tell you what change is, but metaphysics is supposed to tell you what it is for something to change. For example, in chemistry you might learn about different kinds of chemical changes. Science has metaphysical elements, but one way metaphysics differs from science is this idea of generality. I think of metaphysics as the most general enquiry into the nature of reality. Foreign Policy & International Relations.

Metaphysics book