[With quantum computers] you can calculate how many bits are in the universe, how much energy it takes to flip them, how much energy exists, and use that to rule out lots of things about the universe's history. Anything that takes more bit flips couldn't have happened.

The primary consequence of the computational nature of the universe is that the universe naturally generates complex systems, such as life. Although the basic laws of physics are comparatively simple in form, they give rise, because they are computationally universal, to systems of enormous complexity.

Of course, not everybody's willing to go out and do the experiments, but for the people who are willing to go out and do that, - if the experiments don't work, then it means it's not science.

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.

Some folks think life and technology and mind can keep expanding forever. Others say it can't. We are still not clear on that.

There are considerable advantages to using many degrees of freedom to store information, stability and controllability being perhaps the most important.

Indeed, as the above calculation indicates, to take full advantage of the memory space available, the ultimate laptop must turn all its matter into energy.