The quantum theory of parallel universes is not the problem, it is the solution. It is not some troublesome, optional interpretation emerging from arcane theoretical considerations. It is the explanation - the only one that is tenable - of a remarkable and counter-intuitive reality.
David DeutschOur best theories are not only truer than common sense, they make more sense than common sense...
David DeutschTime travel may be achieved one day, or it may not. But if it is, it should not require any fundamental change in world-view, at least for those who broadly share the world view I am presenting in this book.
David DeutschNo precautions, and no precautionary principle, can avoid problems that we do not yet foresee. We need a stance of problem-fixing, not just problem-avoidance.
David DeutschIt is possible to build a virtual-reality generator whose repertoire includes every possible environment.
David DeutschLike every other destruction of optimism, whether in a whole civilisation or in a single individual, these must have been unspeakable catastrophes for those who had dared to expect progress. But we should feel more than sympathy for those people. We should take it personally. For if any of those earlier experiments in optimism had succeeded, our species would be exploring the stars by now, and you and I would be immortal.
David Deutsch