A House-sized Fallacy

You may know that Richard Dawkins is one of my heroes, and today he was giving a speech in Oxford as part of the TED conference. This is how the write-up goes on the BBC website. See if you can guess where I got a little confused:

Our brains had evolved to help us survive within the scale and orders of magnitude within which we exist, said Professor Dawkins.

We think that rocks and crystals are solid when in fact they were made up mostly of spaces in between atoms, he argued.

This, he said, was just the way our brains thought about things in order to help us navigate our “middle sized” world – the medium scale environment – a world in which we cannot see individual atoms.

This idea meant that life was probably “quite common” in the Universe, Professor Dawkins said.

(edited sentence) There’s no way he made that argument without further explanation 🙂 I’ll try to find the exact text…