“We have learned that the satisfaction of instincts cannot be the sole aim of our lives.”

“We have learned that we cannot live alone, at peace; that our own well-being is dependent on the well-being of nations far away. We have learned that we must live as men, and not as ostriches nor as dogs in the manger. We have learned to be citizens of the world, members of the human community.”

“We learn to endure to the end by learning to finish our current responsibilities, and we simply continue doing it all of our lives. We cannot expect to learn endurance in our later years if we have developed the habit of quitting when things get difficult now.”

“Telling us to obey instinct is like telling us to obey 'people.' People say different things: so do instincts. Our instincts are at war. If it is held that the instinct for preserving the species should always be obeyed at the expense of other instincts, whence do we derive this rule of precedence? To listen to that instinct speaking in its own case and deciding in its own favour would be rather simple minded. Each instinct, if you listen to it, will claim to be gratified at the expense of all the rest. By the very act of listening to one rather than to others we have already prejudged the case. If we did not bring to the examination of our instincts a knowledge of their comparative dignity we could never learn it from them. And that knowledge cannot itself be instinctive: the judge cannot be one of the parties judged: or, if he is, the decision is worthless and there is no ground for placing preservation of the species above self-preservation or sexual appetite.”

“We cannot love something solely because it has been ignored. It must also be worthy of our attention. ”

“Our aim as scientists is objective truth; more truth, more interesting truth, more intelligible truth. We cannot reasonably aim at certainty. Once we realize that human knowledge is fallible, we realize also that we can never be completely certain that we have not made a mistake.”