'Conservation' (the conservation law) means this ... that there is a number, which you can calculate, at one moment-and as nature undergoes its multitude of changes, this number doesn't change. That is, if you calculate again, this quantity, it'll be the same as it was before. An example is the conservation of energy: there's a quantity that you can calculate according to a certain rule, and it comes out the same answer after, no matter what happens, happens.

All mass is interaction.

If we want to solve a problem that we have never solved before, we must leave the door to the unknown ajar.

That is the logical tight-rope on which we have to walk if we wish to interpret nature.

The worthwhile problems are the ones you can really solve or help solve, the ones you can really contribute something to... No problem is too small or too trivial if we can really do something about it.

Work hard to find something that fascinates you.

There in wine is found the great generalization: all life is fermentation.