‘What is possible?’ looks at possibilities. Are they things? Do they have any kind of being? Or are they a mere fabrication: things we can think about but which are not really a part of the world? Two accounts are given: firstly, the possible worlds account where every possibility of our world is actual at some other world, meaning as many worlds as there are possibilities. The other is David Armstrong's Combinatorial Theory of Possibility: for something to be possible, it can suffice just that the particular and the property exist that would, if they were combined, constitute it. They could form a recombination that no one ever thinks of.