A maxim is a conclusion upon observation of matters of fact, and is merely speculative; a "principle" carries knowledge within itself, and is prospective.
Capitalism justified itself and was adopted as an economic principle on the express ground that it provides selfish motives for doing good, and that human beings will do nothing except for selfish motives
Law grows, and though the principles of law remain unchanged, yet (and it is one of the advantages of the common law) their application is to be changed with the changing circumstances of the times. Some persons may call this retrogression, I call it progression of human opinion.
My interest in science was always essentially limited to the study of principles.... That I have published so little is due to this same circumstance, as the great need to grasp principles has caused me to spend most of my time on fruitless pursuits.
The only objects of practical reason are therefore those of good and evil. For by the former is meant an object necessarily desired according to a principle of reason; by the latter one necessarily shunned, also according to a principle of reason.
[the virtues] cannot exist without Prudence. A proof of this is that everyone, even at the present day, in defining Virtue, after saying what disposition it is [i.e. moral virtue] and specifying the things with which it is concerned, adds that it is a disposition determined by the right principle; and the right principle is the principle determined by Prudence.
A person who has truly realized the principle of nonviolence has the God given strength for his weapon, and the world has not yet known anything that can match it.
Nature herself, as has been often said, requires that we should be able, not only to work well, but to use leisure well; for, as I must repeat once again, the first principle of all action is leisure. Both are required, but leisure is better than occupation and is its end.
Thanks to my fortunate idea of introducing the relativity principle into physics, you (and others) now enormously overrate my scientific abilities, to the point where this makes me quite uncomfortable.