If there is one conclusion which imposes itself before all others as a result of the inquiry we have made, it is the ambiguity hidden in the sense of the term "physical reality". This is founded in turn upon the underlying polymorphism of the human way of knowing reality. The neglect of some elements of this polymorphic consciousness, or undue emphasis on certain aspects of it are the roots from which spring a multiplicity of epistemological difficulties; for in every question there is a hidden structure directing implicitly the search for answers, and prior even to the formulation of the answer and imposing a structure upon the answer even before it is formulated. This hidden structure is the domain of intentionality and, like the nine-tenths of an iceberg below water, it lies perilously below the level of our cognitive activities. Because of failure to appreciate this, many ontological and epistemological discussions, especially wherever positivism or linguistic analysis is dominant, tend to founder; for, in such cases, problems are generally formulated uniquely in the light of the one-tenth that is in public view. By saying that the human way of knowing is polymorphic, we mean that it is a composite act in which many different activities take part in subordinated roles. Three activities are particularly prominent in such an act; viz., empirical intuition, conceptual understanding and rational affirmation (or judgement). Still it is one act and not many acts; since its purpose is to express a single, if composite, object of knowledge. However, the polymorphism of human consciousness creates many problems. Some of its elements, for instance, may be overlooked. Or alternatively, the diversity of its activities may be recognised but divided into two classes: one constituting the class which really knows reality and which can be used to define the sense of the term "reality" (since reality is, by supposition, its object), and a second class which is considered inessential to this knowledge either because it constitutes merely a provisional or imperfect stage of knowledge or because it provides us merely with criteria of reality which are subjective and extrinsic to the essential definition of reality. We have had occasion to describe the two extremes of simplification: empiricism which tends to devaluate conceptual knowledge and to emphasise the act of empirical intuition, as the essential cognitive act defining (for us) the sense of the term "reality", and rationalism which tends to devaluate empirical knowledge and to see the mind's essential function as that of defining conceptually the essences of real things.