EPISTEMOLOGY is the scientific study of what all other sciences presuppose without examining it: cognition itself. It is thus a philosophical science, fundamental to all other sciences. Only through epistemology can we learn the value and significance of all insight gained through the other sciences. Thus it provides the foundation for all scientific effort. It is obvious that it can fulfill its proper function only by making no presuppositions itself, as far as this is possible, about man's faculty of knowledge. This is generally accepted. Nevertheless, when the better-known systems of epistemology are more closely examined it becomes apparent that a whole series of presuppositions are made at the beginning, which cast doubt on the rest of the argument. It is striking that such hidden assumptions are usually made at the outset, when the fundamental problems of epistemology are formulated. But if the essential problems of a science are misstated, the right solution is unlikely to be forthcoming. The history of science shows that whole epochs have suffered from innumerable mistakes which can be traced to the simple fact that certain problems were wrongly formulated. To illustrate this, we need not go back as far as Aristotle's physics  or Raymond Lull's Ars Magna;  there are plenty of more recent examples. For instance, innumerable problems concerning the purpose of rudimentary organs of certain organisms could only be rightly formulated when the condition for doing so had first been created through the discovery of the fundamental law of biogenesis.  While biology was influenced by teleological views, the relevant problems could not be formulated in a way which could lead to a satisfactory answer. For example, what fantastic ideas were entertained concerning the function of the pineal gland in the human brain, as long as the emphasis was on its purpose! Then comparative anatomy threw some light on the matter by asking a different question; instead of asking what the organ was “for,” inquiry began as to whether, in man, it might be merely a remnant from a lower level of evolution. Another example: how many physical questions had to be modified after the discovery of the laws of the mechanical equivalent of heat and of conservation of energy!  In short, success in scientific research depends essentially on whether the problems can be formulated rightly. Even though epistemology occupies a very special place as the basis presupposed by the other sciences, nevertheless, successful progress can only be expected when its fundamental problems are correctly formulated.
The discussion which follows aims so to formulate the problem of cognition that in this very formulation it will do full justice to the essential feature of epistemology, namely, the fact that it is a science which must contain no presuppositions. A further aim is to use this philosophical basis for science to throw light on Johann Gottlieb Fichte's philosophy of science.  Why Fichte's attempt in particular to provide an absolutely certain basis for the sciences is linked to the aims of this essay, will become clear in due course.