Ludwik Fleck

"A truly isolated investigator is impossible... An isolated investigator without bias and tradition, without forces of mental society acting upon him, and without the effect of the evolution of that society, would be blind and thoughtless. Thinking is a collective activity (…). Its product is a certain picture, which is visible only to anybody who takes part in this social activity, or a thought which is also clear to the members of the collective only. What we do think and how we do see depends on the thought-collective to which we belong."

"The individual within the collective is never, or hardly ever, conscious of the prevailing thought style, which almost always exerts an absolutely compulsive force upon his thinking and with which it is not possible to be at variance."

"At the present time we are so fortunate as to witness the spectacle of the birth, the creation, of a new style of thinking... Sooner or later much will change: the law of causality, the concepts of objectivity and subjectivity. Something else will be demanded from scientific solutions and different problems will be regarded as important. Much that has been proven will be found unproven, and much of what was never proven will turn out to be superfluous."

"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."

"If we define thought collective as a community of persons mutually exchanging ideas or maintaining intellectual interaction, we will find by implication that it also provides the special carrier for the historical development of any field of thought, as well as for the given stock of knowledge and level of culture. This we have designated thought style."

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