Throughout space there is energy. Is this energy static or kinetic? If static our hopes are in vain; if kinetic – and this we know it is, for certain – then it is a mere question of time when men will succeed in attaching their machinery to the very wheelwork of nature.
Three possible solutions of the great problem of increasing human energy are answered by the three words: food, peace, work.
Iron rusts from disuse; stagnant water loses its purity and in cold weather becomes frozen; even so does inaction sap the vigor of the mind.
There is not the slightest indication that [nuclear energy] will ever be obtainable. It would mean that the atom would have to be shattered at will.
The release of atomic energy has not created a new problem. It has merely made more urgent the necessity of solving an existing one.
The mass of a body is a measure of its energy content.[Die Masse eines Körpers ist ein Maß für dessen Energiegehalt.]
I felt my energy return and that I said to myself, in any event I’ll recover from it, I’ll pick up my pencil that I put down in my great discouragement and I’ll get back to drawing, and from then on, it seems to me, everything has changed for me.