The guiding motto in the life of every natural philosopher should be, seek simplicity and distrust it.
Not ignorance, but ignorance of ignorance, is the death of knowledge.
In formal logic, a contradiction is the signal of defeat, but in the evolution of real knowledge it marks the first step in progress toward a victory.
No one who achieves success does so without acknowledging the help of others. The wise and confident acknowledge this help with gratitude.
Art is the imposing of a pattern on experience, and our aesthetic enjoyment is recognition of the pattern.
True courage is not the brutal force of vulgar heroes, but the firm resolve of virtue and reason.
The art of progress is to preserve order amid change and to preserve change amid order.
If a dog jumps into your lap, it is because he is fond of you; but if a cat does the same thing, it is because your lap is warmer.
No period of history has ever been great or ever can be that does not act on some sort of high, idealistic motives, and idealism in our time has been shoved aside, and we are paying the penalty for it.
It takes an extraordinary intelligence to contemplate the obvious.
Periods of tranquility are seldom prolific of creative achievement. Mankind has to be stirred up.
The absolute pacifist is a bad citizen; times come when force must be used to uphold right, justice and ideals.
Art attracts us only by what it reveals of our most secret self.
Seek simplicity but distrust it.
But you can catch yourself entertaining habitually certain ideas and setting others aside; and that, I think, is where our personal destinies are largely decided.
I have suffered a great deal from writers who have quoted this or that sentence of mine either out of its context or in juxtaposition to some incongruous matter which quite distorted my meaning, or destroyed it altogether.
Familiar things happen, and mankind does not bother about them. It requires a very unusual mind to undertake the analysis of the obvious.
Intelligence is quickness to apprehend as distinct form ability, which is capacity to act wisely on the thing apprehended.
When you're average, you're just as close to the bottom as you are the top.
Wisdom alone is true ambition's aim, wisdom is the source of virtue and of fame; obtained with labour, for mankind employed, and then, when most you share it, best enjoyed.