The aim of Kant's radicalism like Copernicus is to achieve knowledge not from prerequisites but preassume it and in accordance with its requirements, work out the prerequisites which will justify the preassumed knowledge. This will cause subordination of prerequisite formation to a certain outline. This will exclude poking in perception and provide "the only" way that guarantees confirmation of the perception possibilities. Thus, the preassumption of knowledge is the basis of Kant's theoretical philosophy.

It is connected with the argumentation of perception impossibility in a different way, as well as requirement of synthetic – a priori judgment.