A great man, who was convinced that the truths of political and moral science are capable of the same certainty as those that form the system of physical science, even in those branches like astronomy that seem to approximate mathematical certainty. He cherished this belief, for it led to the consoling hope that humanity would inevitably make progress toward a state of happiness and improved character even as it has already done in its knowledge of the truth.

Enjoy your own life without comparing it with that of another.[or you will create disappointment and envy, as every other person has something, small or large, better than you. Remember at these times what you have rather than what you don't and be grateful]

The penalty of death is the only one that makes an injustice absolutely irreparable; from which it follows that the existence of the death penalty implies that one is exposed to committing an irreparable injustice; from which it follows that it is unjust to establish it. This reasoning appears to us to have the force of a demonstration.

People still retain the errors of their childhood, their nation, and their age, long after they have accepted the truths needed to refute them.

The truth belongs to those who seek it, not to those who claim to own it.

If it is possible to have a linear unit that depends on no other quantity, it would seem natural to prefer it. Moreover, a mensural unit taken from the earth itself offers another advantage, that of being perfectly analogous to all the real measurements that in ordinary usage are also made upon the earth, such as the distance between two places or the area of some tract, for example. It is far more natural in practice to refer geographical distances to a quadrant of a great circle than to the length of a pendulum.

Men do not often dare to avow, even to themselves, the slow progress reason has made in their minds; but they are ready to follow it if it is presented to them in a lively and striking manner, and forces them to recognize it.