“Men act like brutes in so far as the sequences of their perceptions arise through the principle of memory only, like those empirical physicians who have mere practice without theory.”

Therefore, I have attacted [the problem of the catenary] which I had hitherto not attempted, and with my key [the differential calculus] happily opened its secret. Acta eruditorum

The greatness of a life can only be estimated by the multitude of its actions. We should not count the years, it is our actions which constitute our life.

The pleasure we obtain from music comes from counting, but counting unconsciously. Music is nothing but unconscious arithmetic.

God makes nothing without order, and everything that forms itself develops imperceptibly out of small parts.

The Divine Spirit found a sublime outlet in that wonder of analysis, that portent of the ideal world, that amphibian between being and not-being, which we call the imaginary root of negative unity.

The present is saturated with the past and pregnant with the future.

Our reasonings are grounded upon two great principles, that of contradiction, in virtue of which we judge false that which involves a contradiction, and true that which is opposed or contradictory to the false.

The larger the mass of collected things, the less will be their usefulness. Therefore, one should not only strive to assemble new goods from everywhere, but one must endeavor to put in the right order those that one already possesses.

Take what you need, do what you should, you will get what you want.

Of what use would it be to you, sir, to become King of China on condition that you forgot what you have been? Would it not be the same as if God, at the same time he destroyed you, created a King in China?

I have said more than once, that I hold space to be something purely relative, as time; an order of coexistences, as time is an order of successions.

A distinction must be made between true and false ideas, and that too much rein must not be given to a man’s imagination under pretext of its being a clear and distinct intellection.

He who understands Archimedes and Apollonius will admire less the achievements of the foremost men of later times.

Music is the pleasure the human mind experiences from counting without being aware that it is counting.

I hold that the mark of a genuine idea is that its possibility can be proved, either a priori by conceiving its cause or reason, or a posteriori when experience teaches us that it is in fact in nature.

We may say, that not only the soul (the mirror of an indestructible universe) is indestructible, but also the animal itself is, although its mechanism is frequently destroyed in parts.

But the perception of life as an organic unity is a slow achievement, and depends for its growth on a people’s entry into the main current of world-events.

In England we have come to rely upon a comfortable time-lag of fifty years or a century intervening between the perception that something ought to be done and a serious attempt to do it.

But that citizen’s perception was also at one with the truth in recognizing that the very brutality of the means by which the IRA were pursuing change was destructive of the trust upon which new possibilities would have to be based.

Even in the 1950s, President Eisenhower was concerned about what he called a campaign of hatred of the U.S. in the Arab world, because of the perception on the Arab street that it supported harsh and oppressive regimes to take their oil.

Perception’s not reality.

The feminine character, the feminine perceptions, intuitions, delicacy, sympathy, quickness, are more responsive to natural forms and influences than is the masculine mind.

The process of shaping opinion, attitudes, and perceptions was termed the ‘engineering of consent’ by one of the founders of the modern public relations industry, Edward Bernays.

I don’t dabble and spend much mind or time dealing with, I don’t know, people’s perceptions of me. I truly don’t.