Quotes from Ludwik Fleck

The current state of knowledge remains vague when history is not considered, just as history remains vague without substantive knowledge about the current state.

Cognition modifies the knower so as to adapt him harmoniously to his acquired knowledge.

Whatever is known has always seemed systematic, proven, applicable, and evident to the knower. Every alien system of knowledge has likewise seemed contradictory, unproven, inapplicable, fanciful, or mystical. May not the time have come to assume a less egocentric, more general point of view and to speak of comparative epistemology?

Very different thought styles are used for one and the same problem more often than are very closely related ones. It happens more frequently that a physician simultaneously pursues studies of a disease from a clinical-medical or bacteriological viewpoint together with that of the history of civilization, than from a clinical-medical or bacteriological one together with a purely chemical one.

Thoughts pass from one individual to another, each time a little transformed, for each individual can attach to them somewhat different associations. Strictly speaking, the receiver never understands the thought exactly in the way that the transmitter intended it to be understood. After a series of such encounters, practically nothing is left of the original content. Whose thought is it that continues to circulate?

The explanation given to any relation can survive and develop within a given society only if this explanation is stylized in conformity with the prevailing thought style.

The current state of knowledge remains vague when history is not considered, just as history remains vague without substantive knowledge about the current state.

La introducción en un campo de conocimiento es más un adoctrinamiento que un estímulo del pensamiento crítico-científico. El tiempo de aprendizaje —en la ciencia tanto como en la industria, el arte o la religión— se caracteriza por una «sugestión de ideas puramente autoritaria».

Once a structurally complete and closed system of opinions consisting of many details and relations has been formed, it offers enduring resistance to anything that contradicts it.

We have even lost any critical insight we may once have had into the organic basis of perception, taking for granted the basic fact that a normal person has two eyes. We have nearly ceased to consider this as even knowledge at all and are no longer conscious of our own participation in perception. Instead, we feel a complete passivity in the face of a power that is independent of us; a power we call "existence" or "reality.

In science, just as in art and in life, only that which is true to culture is true to nature.

Biology taught me that a field undergoing development should be investigated always from the viewpoint of its past development. Who today would study anatomy without embryology? In exactly the same way epistemology without historical and comparative investigations is no more than an empty play on words or an epistemology of the imagination.

History cannot be logically constructed any more than a scientific event, if only because it involves the process of vague and indefinable concepts which are about to crystallize. The more detailed and differentiated the description for any field of thought, the more complex, interrelated, and mutually dependent in definition will be its concepts. They become a tangle impossible to unravel logically, an organic structure produced by mutual development and with interacting components.