Alexander Vilenkin, theoretical physicist: "The laws of physics that describe the appearance of the universe should have some Platonic existence outside of matter, space, and time. We can ask what is the medium in which they exist? Often people think the medium of mathematics is the mind; mathematics is a human invention. Mathematicians actually often think they are discovering mathematics, that mathematics exists objectively. So, whichever it is, there is some Platonic realm in which the mathematical laws of physics exist even prior the universe."