Fear not dead rivals, but living enemies!
Undead appear only to those who need to see them.
Jealousy is a sign of love.
It is seldom that the thing you desire so passionately is not guarded by someone with the same passion.
A mistress you can part with, but a wife, damn it, is something else: to her you are bound forever - whether you are near or far from each other.
Miserliness dries up the soul.
The feeble-minded always see everything through a veil of mourning.
An advice is more than a service.
A passion blinds even the most temperate minds.
Happiness in solitude is not complete happiness.
That's right: youth rejoices, old age scolds.
He who takes revenge sometimes regrets it; he who forgives is never sorry.
Houses, like people, have their soul and their face that reflects the inner essence.
The higher in the sky a mighty eagle flies, the longer it must rest on earth.
God is a gaseous vertebrate.
It is a great mistake to think that a sense of duty and compulsion can contribute to learning the joy of looking and searching.
Wireless telegraphy can be easily understood. An ordinary telegraph is like a very long cat: pull its tail in New York and it meows in Los Angeles. The wireless telegraph is the same thing, but without the cat.
In physics, substantial success has often been achieved by drawing an analogy between unrelated events.
Imagination is more important than knowledge.
Everything should be described as simply as possible, but not simpler than possible.
In science, all ideas were born out of a dramatic conflict between reality and our attempts to understand it.
Everyone knows from childhood that one or the other is impossible. However, there is always an ignoramus who does not know this. It is he who makes a discovery.
The most important thing in man's life is what he thinks and how he thinks, and not what he does or feels.
God does not play dice.
Gravity cannot be responsible for those whom love brings down.
For us staunch physicists, the distinction between past, present, and future is no more than an illusion, albeit a very haunting one.
If you will not sin against reason, you cannot, in general, achieve anything.
If the theory of relativity is confirmed, then the German will say: I am German, and the French: I am a citizen of the world; if, however, my theory is rejected, the French will declare me a German, and the Germans, a Jew.
If I devoted myself to science, guided not only by purely external motives, such as the making of money or the satisfaction of my own ambition, and not because (at least, not for this reason alone) I considered it a kind of sport, an exercise of the mind, which gives me pleasure, then a question must represent me as a supporter of the ardent interest of science: what end must and must the science to which I have devoted myself set before me? How true are his results today? What is so significant in them and what depends on its accidental development?
There are only two infinite things: the Universe and stupidity. Although, regarding the Universe I'm not too sure.