If all of this, all the life of a stream of water, can be nothing but a pile of atoms, how much more is possible?

The basis of action on love, the brotherhood of all men, the value of the individual... the humility of the spirit.

I have argued flying saucers with lots of people. I was interested in possible. They do not appreciate that the problem is not to demonstrate whether it's possible or not but whether it's going on or not.

Science is a way for us to not fool ourselves.

Words can be meaningless. If they are used in such a way that no sharp conclusions can be drawn.

All theoretical chemistry is really physics; and all theoretical chemists know it.

I can live with doubt and uncertainty and not knowing. I think it is much more interesting to live not knowing than to have answers that might be wrong. If we will only allow that, as we progress, we remain unsure, we will leave opportunities for alternatives. We will not become enthusiastic for the fact, the knowledge, the absolute truth of the day, but remain always uncertain … In order to make progress, one must leave the door to the unknown ajar.