There is more than just grandeur in this view of life, bleak and cold though it can seem from under the security blanket of ignorance. There is deep … - Richard Dawkins

When we look at a solid lump of iron or rock, we are 'really' looking at what is almost entirely empty space. It looks and feels solid and opaque because our sensory systems and brains find it convenient to treat it as solid and opaque. It is convenient for the brain to represent a rock as solid because we can't walk through it. 'Solid' is our way of experiencing things that we can't walk through or fall throug, because of the electromagnetic forces between atoms. 'Opaque' is the experience we have when light bounces off the surface of an object, and none of it goes through.

Evidence is the only good reason to believe anything

This is where they come into their own, for there's money in hope: the more desperate the hope, the richer the pickings.