What Can You Really Know? by Freeman Dyson | The New York Review of Books: Holt is a splitter and I am a lumper. Philosophers are mostly splitters, dividing their ways of thinking into narrow specialties such as theism or deism or humanism or panpsychism or axiarchism. Examples of each of these isms are to be seen in Holt’s collection. I find it more convenient to lump them into two big groups, one obsessed with matter and the other obsessed with mind. Holt asks them to explain why the world exists. For the materialists, the question concerns the origin of space and time and particles and fields, and the relevant branch of science is physics. For the Platonists, the question concerns the origin of meaning and purpose and consciousness, and the relevant science is psychology.