That was one of the advantages of his age, that he could be sure of his mastery in every moment.

Order and simplification are the first steps towards mastery of a subject

The mastery of nature is vainly believed to be an adequate substitute for self mastery.

Also he saw one dog, that would neither conciliate nor obey, finally killed in the struggle for mastery.

If you can win complete mastery over self, you will easily master all else. To triumph over self is the perfect victory

If people knew how hard I worked to get my mastery, it wouldn’t seem so wonderful at all.

No society has ever yet been able to handle the temptations of technology to mastery, to waste, to exuberance, to exploration and exploitation. We have to learn to cherish this earth and cherish it as something that’s fragile, that’s only one, it’s all we have. We have to use our scientific knowledge to correct the dangers that have come from science and technology.