Claude Bernard Quotes

Indeed, proof that a given condition always precedes or accompanies a phenomenon does not warrant concluding with certainty that a given condition is the immediate cause of that phenomenon. It must still be established that, when this condition is removed, the phenomenon will no longer appear.

[S]cience, in humbling our pride, proportionately increases our power.

A great surgeon performs operations for stone by a single method; later he makes a statistical summary of deaths and recoveries, and he concludes from these statistics that the mortality law for this operation is two out of five. Well, I say that this ratio means literally nothing scientifically and gives us no certainty in performing the next operation; for we do not know whether the next case will be among the recoveries or the deaths. What really should be done, instead of gathering facts empirically, is to study them more accurately, each in its special determinism. We must study cases of death with great care and try to discover in them the cause of mortal accidents so as to master the cause and avoid the accidents.

Leçons sur les Phénomènes de la Vie Communs aux Animaux et aux Végétaux (1878-1879).

[T]heories are only hypotheses, verified by more or less numerous facts. Those verified by the most facts are the best; but even then they are never final, never to be absolutely believed.

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.

Men who have excessive faith in their theories or ideas are not only ill prepared for making discoveries; they also make very poor observations.

If I had to define life in a word, it would be: Life is creation.

Leçons sur les Phénomènes de la Vie Communs aux Animaux et aux Végétaux.

A modern poet has characterized the personality of art and the impersonality of science as follows: Art is I: Science is We.

In sciences of observation, man observes and reasons experimentally, but he does not experiment; and in this sense we might say that a science of observation is a passive science. In sciences of experimentation, man observes, but in addition he acts on matter, analyzes its properties and to his own advantage brings about the appearance of phenomena which doubtless always occur according to natural laws, but in conditions which nature often has not yet achieved. With the help 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 in the experimental sciences.

[A] living organism is nothing but a wonderful machine.

Considered in itself, the experimental method is nothing but reasoning by whose help we methodically submit our ideas to experience,—the experience of facts.

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

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