It is far better for a man to go wrong in freedom than to go right in chains.
Irrationally held truths may be more harmful than reasoned errors.
Science and literature are not two things, but two sides of one thing.
The great end of life is not knowledge but action.
The results of political changes are hardly ever those which their friends hope or their foes fear.
The foundation of all morality is to have done, once and for all, with lying; to give up pretending to believe that for which there is no evidence, and repeating unintelligible propositions about things beyond the possibilities of knowledge.
Surely there is a time to submit to guidance and a time to take one’s own way at all hazards.
A man has no reason to be ashamed of having an ape for his grandfather. If there were an ancestor whom I should feel shame in recalling it would rather be a man who plunges into scientific questions with which he has no real acquaintance, only to obscure them by an aimless rhetoric...
Genius, as an explosive power, beats gunpowder hollow.
To quarrel with the uncertainty that besets us in intellectual affairs would be about as reasonable as to object to live one’s life with due thought for the morrow because no man can be sure he will alive an hour hence.
The student of Nature wonders the more and is astonished the less, the more conversant he becomes with her operations; but of all the perennial miracles she offers to his inspection, perhaps the most worthy of admiration is the development of a plant or of an animal from its embryo.
Matter and force are the two names of the one artist who fashions the living as well as the lifeless.
Rome is the one great spiritual organisation which is able to resist and must, as a matter of life and death, the progress of science and modern civilization.
The only people, scientific or other, who never make mistakes are those who do nothing.
If a man cannot see a church, it is preposterous to take his opinion about its altar-piece or painted window.
Only one absolute certainty is possible to man, namely that at any given moment the feeling which he has exists.
Not only do I disbelieve in the need for compensation, but I believe that the seeking for rewards and punishments out of this lifeleads men to a ruinous ignorance of the fact that their inevitable rewards and punishments are here.
The method of scientific investigation is nothing but the expression of the necessary mode of working of the human mind. It is simply the mode in which all phenomena are reasoned about, rendered precise and exact.
Do what you can to do what you ought, and leave hoping and fearing alone.
True science and true religion are twin sisters, and the separation of either from the other is sure to prove the death of both. Science prospers exactly in proportion as it is religious; and religion flourishes in exact proportion to the scientific depth and firmness of its basis.