Nothing in life is certain except death, taxes and the second law of thermodynamics. All three are processes in which useful or accessible forms of some quantity, such as energy or money, are transformed into useless, inaccessible forms of the same quantity. That is not to say that these three processes don't have fringe benefits: taxes pay for roads and schools; the second law of thermodynamics drives cars, computers and metabolism; and death, at the very least, opens up tenured faculty positions.

Computers are famous for being able to do complicated things starting from simple programs.

If you wanted to build the most powerful computer you could, you can't do better than including everything in the universe that's potentially available.

I have not proved that the universe is, in fact, a digital computer and that it's capable of performing universal computation, but it's plausible that it is.

When it comes to their capacity to screw things up, computers are becoming more human every day.

Science has an uncomfortable way of pushing human beings from center stage. In our prescientific stories, humans began as the focal point of Nature, living on an Earth that was the center of the universe. As the origins of the Earth and of mankind were investigated more carefully, it became clear that Nature had other interests beyond people, and the Earth was less central than previously hoped. Humankind was just one branch of the great family of life, and the Earth is a smallish planet orbiting an unexceptional sun quite far out on one arm of a run-of-the-mill spiral galaxy.

Every physical system registers information, and just by evolving in time, by doing its thing, it changes that information, transforms that information, or, if you like, processes that information.