http://en.wikipedia.org/wiki/Ludwik_Fleck
http://fleck.umcs.lublin.pl/teksty.sady.introduction.htm
Another important hint can possibly be provided by Fleck's remarks that the passive element can sometimes be transformed, within a different thought style, into an active one. Elements developed within older thought styles, becoming autonomous, could give rise to new systems. Possibly, an important role is played by misunderstandings during the intercollective exchange of ideas. Words change their meanings in many ways and this in turn creates new facts and opens new cognitive possibilities. In this way, an avalanche of transformations can begin, as within scientific systems there are internal connections so that every new fact changes all facts known before.
His remarks on what happens in the result of such transformation are much more important. Fleck opposes the view that old, false statements are replaced by new ones, more true then their predecessors. Before and after the scientific revolution "the same" words have different meanings, so we do not talk more truly about the same facts, objects, etc. but rather we talk in a different way about different things.
As a result, a comparison of the cognitive advantages of incommensurable theoretical systems is not possible. All debates between adherents of different thought styles consist almost entirely of misunderstandings. Members of both parties are talking of different things (although they are usually under an illusion that they are talking about, the same thing). They are applying different methods and criteria of correctness (although they are usually under an illusion that their arguments are universally valid and if their opponents do not want to accept them, then they are either stupid or malicious).
IV. There are not only gains but also losses involved in the changing of a thought style. We become able to see new facts but at the same time we lose ability to perceive something that was perceived by our predecessors. For ancient thinkers things of which their world was composed had deep, symbolic meaning - those things were related to gods, good and evil, and destiny. Within some thought styles numbers were not only tools of description but were significant in themselves and formed meaningful connections. All those senses disappeared in our times. Contemporary thinkers read old books with the feeling of superiority - for they cannot understand that ancient people had more to say about what was of superior value for them.
Scientific thought styles are distinguished by the larger number of passive elements relative to the number of active ones. There are passive elements in every thought style, even in myths or fairy-tales. However, internal connections within mythical systems are more detached and that is why the world appears to the adherents of such thought styles as unstable and full of miracles. In contrast, scientific thought styles are characterized by a relatively large degree of internal connections, and this leads to the belief that there is objective reality that exists independently of our thoughts, feelings and wishes.