Claude Bernard


French Physiologist

Author Quotes

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.

Hatred is the most clear- sighted, next to genius

In the philosophic sense, observation shows and experiment teaches.

Mediocre men often have the most acquired knowledge

Put off your imagination, as you put off your overcoat, when you enter the laboratory. Put it on again, as you put on your overcoat, when you leave.

The experiment is complete only after the counterproof, just as analysis is never complete except after synthesis. In physiology we cannot make a synthesis, but we can carry out the control experiment - or counterproof.

The physiologist is not a man of the world, he is a scientist, a man caught and absorbed by a scientific idea that he pursues; he no longer hears the cries of the animals, no longer sees the flowing blood, he sees only his idea: organisms that hide from him problems that he wants to discover. He doesn't feel that he is in a horrible carnage; under the influence of a scientific idea, he pursues with delight a nervous filament inside stinking and livid flesh that for any other person would be an object of disgust and horror.

Tout est poison, rien n'est poison, tout est une question de dose. Everything is poisonous, nothing is poisonous, it is all a matter of dose.

When he does not know what he ought to want, he should know what his enemy wants - and want the contrary.

I am convinced that I have also served science in this way: I have stimulated work

In the sciences, there is doubtless a very close connection between observation and experimentation. Nevertheless, it is necessary to distinguish them because (otherwise) everything would become confused.

Mediocre men often have the most acquired knowledge. It is in the darker. It is in the darker regions of science that great men are recognized; they are marked by ideas which light up phenomena hitherto obscure and carry science forward.

Real science exists, then, only from the moment when a phenomenon is accurately defined as to its nature and rigorously determined in relation to its material conditions, that is, when its law is known. Before that, we have only groping and empiricism.

The experimenter who does not know what he is looking for will never understand what he finds.

The science of life is a superb and dazzlingly lighted hall which may be reached only by passing through a long and ghastly kitchen.

True science teaches us to doubt and to abstain from ignorance.

When one calls a new fact a discovery, the fact itself is not a discovery, but rather the new idea derived from it.

I am the leader of the current physiological movement.

In these researches I followed the principles of the experimental method that we have established, i.e., that, in presence of a well-noted, new fact which contradicts a theory, instead of keeping the theory and abandoning the fact, I should keep and study the fact, and I hastened to give up the theory.

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.

Science admits no exceptions; otherwise there would be no determinism in science, or rather, there would be no science.

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.

The stability of the internal medium is a primary condition for the freedom and independence of certain living bodies in relation to the environment surrounding them.

True science teaches us to doubt and, in ignorance, to refrain.

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.

Author Picture
First Name
Last Name
Birth Date
Death Date

French Physiologist