“When entering on new ground we must not be afraid to express even risky ideas so as to stimulate research in all directions. As Priestley put it, we must not remain inactive through false modesty based on fear of being mistaken.”

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.

With the aid of these active experimental sciences man becomes an inventor of phenomena, a real foreman of creation; and under this head we cannot set limits to the power that he may gain over nature through future progress of the experimental sciences.

There’s a proud modesty in merit; averse from asking, and resolved to pay ten times the gifts it asks.

Do as much as possible, and talk of yourself as little as possible.

Travel makes one modest. You see what a tiny place you occupy in the world.

The awareness of our own strength makes us modest.

Perdomita Britannia et statim omissa. Britain was conquered and immediately lost.

The approbation of others is a stimulus of which one must sometimes be wary. The feeling of one’s own strength makes one modest.

Legions and fleets are not such sure bulwarks of imperial power as a numerous family

When a woman has lost her chastity she will shrink from nothing.