What science cannot tell us, mankind cannot know.
No great achievement is possible without persistent work.
The good life is one inspired by love and guided by knowledge.
Three passions, simple but overwhelmingly strong, have governed my life: the longing for love, the search for knowledge, and unbearable pity for the suffering of mankind.
There was, I think, never any reason to believe in any innate superiority of the male, except his superior muscle.
A marriage is likely to be called happy if neither party ever expected to get much happiness out of it.
The mind is a strange machine which can combine the materials offered to it in the most astonishing ways.
When the journey from means to end is not too long, the means themselves are enjoyed if the end is ardently desired.
The sentiments of an adult are compounded of a kernal of instinct surrounded by a vast husk of education.
For the learning of every virtue there is an appropriate discipline, and for the learning of suspended judgment the best discipline is philosophy.
Religions which have any very strong hold over men’s actions have generally some instinctive basis.
To modern educated people, it seems obvious that matters of fact are to be ascertained by observation, not by consulting ancient authorities. But this is an entirely modern conception, which hardly existed before the seventeenth century.
All who are not lunatics are agreed about certain things : That it is better to be alive than dead, better to be adequately fed than starved, better to be free than a slave.
A smell of petroleum prevails throughout.
My first advice on how not to grow old would be to choose you ancestors carefully.
I do not pretend that birth control is the only way in which population can be kept from increasing. There are others, which, one must suppose, opponents of birth control would prefer.
If a law were passed giving six months to every writer of a first book, only the good ones would do it.
The fundamental defect of Christian ethics consists in the fact that it labels certain classes of acts ‘sins’ and others ‘virtue’ on grounds that have nothing to do with their social consequences.
Psychology often becomes the disease of which it should be the cure.
Of all forms of caution, caution in love is perhaps the most fatal to true happiness.
It is not what the man of science believes that distinguishes him, but how and why he believes it. His beliefs are tentative, not dogmatic; they are based on evidence, not on authority or intuition.