Why do we remember the past, but not the future?

A model is a good model if first it interprets a wide range of observations in terms of a simple and elegant model, and second if the model makes definite predictions that can be tested, and possibly falsified, by observation.

God abhors a naked singularity.

I don't think the human race will survive the next thousand years, unless we spread into space.

There is a very real danger that we will kill everything on this planet now that we have the technological power to do so.

Save water. Shower with your girlfriend.

I think the next [21st] century will be the century of complexity. We have already discovered the basic laws that govern matter and understand all the normal situations. We don't know how the laws fit together, and what happens under extreme conditions. But I expect we will find a complete unified theory sometime this century. The is no limit to the complexity that we can build using those basic laws.