“The fact that knowledge endlessly recedes as the investigator is about to grasp it is what constitutes at the same time his torment and happiness.”

Well-observed facts, though brought to light by passing theories, will never die; they are the material on which alone the house of science will at last be built.

Particular facts are never scientific; only generalization can establish science.

Men who believe too firmly in their theories, do not believe enough in the theories of others. So these despisers of their fellows make experiments only to destroy a theory, instead of to seek the truth.

The true worth of an experimenter consists in his pursuing not only what he seeks in his experiment, but also what he did not seek.

The mental never influences the physical. It is always the physical that modifies the mental, and when we think that the mind is diseased, it is always an illusion.

Science increases our power in proportion as it lowers our pride.

When we meet a fact which contradicts a prevailing theory, we must accept the fact and abandon the theory, even when the theory is supported by great names and generally accepted.

The terrain is everything; the germ is nothing.

The joy of discovery is certainly the liveliest that the mind of man can ever feel.

The experimenter who does not know what he is looking for will not understand what he finds.

The better educated we are and the more acquired information we have, the better prepared shall we find our minds for making great and fruitful discoveries.

A man of science rises ever, in seeking truth; and if he never finds it in its wholeness, he discovers nevertheless very significant fragments; and these fragments of universal truth are precisely what constitutes science.

We must never make experiments to confirm our ideas, but simply to control them.

Everything is poisonous, nothing is poisonous, it is all a matter of dose.

Effects vary with the conditions which bring them to pass, but laws do not vary. Physiological and pathological states are ruled by the same forces; they differ only because of the special conditions under which the vital laws manifest themselves.

Priestley said that each discovery we make shows us many others that should be made.

Whenever he looked he saw the labour of existence; and this labour, recognised as such, was what constituted reality for him. (On Vincent Van Gogh)

History always constitutes the relation between a present and its past. Consequently fear of the present leads to mystification of the past

Sympathy constitutes friendship; but in love there is a sort of antipathy, or opposing passion. Each strives to be the other, and both together make up one whole.

As it must not, so genius cannot be lawless; for it is even that constitutes its genius – the power of acting creatively under laws of its own origination.

Be not merely a man of letters! Let literature be an honorable augmentations to your arms, not constitute the coat or fill the escutcheon!

Evil is… a moral entity and not a created one, an eternal and not a perishable entity: it existed before the world; it constituted the monstrous, the execrable being who was also to fashion such a hideous world. It will hence exist after the creatures which people this world

I think our sexuality is all yet to be recounted and that the rich male literary tradition constitutes a huge obstacle.

Sleep and watchfulness, both of them, when immoderate, constitute disease.