I should teach the world about the 'many worlds' aspect of quantum mechanics. Quantum mechanics is the basic theory of modern physics, and all of its counterintuitive aspects arise from the fact that it is intrinsically many-worlds.

I would emphasise that even classical physics, in its most powerful formulation - called Hamilton-Jacobi theory, named after the nineteenth-century German mathematician Carl Gustav Jakob Jacobi and the nineteenth-century Irish scientist William Rowan Hamilton - is intrinsically many-worlds. So, one can avoid the many-worlds aspect of physics only by rejecting the basic physics of the past 500 years, if expressed in its most elegant mathematical form.

I would then point out that the many-worlds aspect of physics means parallel universes exist - universes in which almost identical analogues of you and I do slightly different things. The many-worlds aspect of physics is the most earthshaking revolution in our picture of physical reality since the Copernican revolution. It completes the Copernican revolution!

Frank Tipler is author of The Physics of Immortality: Modern Cosmology, God and the Resurrection of the Dead (buy this book from Amazon (UK) or Amazon (USA)), and coauthor of The Anthropic Cosmological Principle (buy this book from Amazon (UK) or Amazon (USA)). See his website.