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.

I hope to see the bringing together of all the best educated people of the earth into a worldwide Congress of Scientists.

Enjoy your own life without comparing it with that of another for there will always be others whose lives on the face of it appear better. However just remember and focus on the fact that your life could be much worse and be grateful it isn't. No matter what others or even you may briefly think you are lucky things aren't worse so be grateful.

Under the freest constitution ignorant people are still slaves.

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.

[All phenomena] are equally susceptible of being calculated, and all that is necessary, to reduce the whole of nature to laws similar to those which Newton discovered with the aid of the calculus, is to have a sufficient number of observations and a mathematics that is complex enough.

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.