research was an unattainable ideal, since researchers are locked into thought collectives (or thought-styles). "[P]ure and direct observation cannot exist: in the act of perceiving objects, the observer, i.e. the epistemological subject, is always influenced by the [period] and... environment to which he belongs, that is, by what Fleck calls the thought style."

In Fleck's work, thought style is closely associated with representational style. A "fact" is a relative value, expressed in the language