Th is article is an attempt to present Husserl's phenomenology as a moderate form of rationalism. By 'moderate rationalism' is understood, fi rst, a theory that does not exclude the problem of irrationality, and that comprehends the rational as a correlate of the irrational. Second, it is a theory that performs its analyses by adopting the thesis that evidence can be achieved at many levels and grades. Here perfect evidence can also appear as imperfect. Yet this imperfect evidence (as an equivalent to unreason) can be a subject of evidential inquiry (as an equivalent to reason). Th e argument is that moderate rationalism is connected with the transcendental character of phenomenology and leads to the perennial reconsideration of the question of evidence (Evidenz). A basic claim is that irrationality is to be understood in terms of possible vague levels and grades of evidence. By developing 'moderate rationalism' thus understood, one is interested in understanding reason, that is, in the question of the essence of reason in its correlation with unreason. Here, moderate rationalism is directly interested not in rational arguments, but in 'elucidation' of reason. It is argued that phenomenology of reason also investigates 'irrational evidence,' for example, background evidence, evidence with respect to others, as well as all forms of fallible evidence. Th erefore, the main question of moderate rationalism is Husserl's question of evidence.