The prospective colonization of space responds, not to the particular problems of the American nation, or of any other nation, but to those of mankind as a whole... In an ideal view, such an undertaking by mankind as a whole would tend to divert it from its present preoccupation with international conflict, would tend to channel its energies into the pursuit of a great common purpose.

It is almost impossible to convince people who are under the influence of ideological bigotry that whose whom they regard as belonging to the enemy species are human.

For a few ticks of the clock I am here, uncomprehending, attempting to make some record or memorial of this eternal passage, like a traveler in a strange country through which he is being hurried on a schedule not of his making and for a purpose he does not understand.

It is the nature of slavery to render its victims so abject that at last, fearing to be free, they multiply their own chains. You can liberate a freeman, but you cannot liberate a slave.

To snatch the passing moment and examine it for signs of eternity is the noblest of occupations.

The revolt against freedom, which can be traced back so far, is associated with a revolt against reason that [gives] sentiment primacy to evaluate actions and experiences according to the subjective emotions with which they are associated.

To me the bicycle is in many ways a more satisfactory invention than the automobile. It is consonant with the independence of man because it works under his own power entirely. There is no combustion of some petroleum product..to set the pedals going. Purely mechanical instruments like watches and bicycles are to be preferred to engines that depend on the purchase of power from foreign sources....The price of power is enslavement.