PHENOMENON. — From the Greek φαίνωμα, “to show, bring to light” (root φα, “to shine,” “light”), it signifies appearance, presentation: everything that appears and is shown to consciousness, hence all data of external and internal, subjective and objective experience, according to the primitive meaning of the term, may be called a phenomenon. In this sense, the term is sometimes taken as a synonym for fact, although more precisely phenomenon adds to the meaning of fact or event the actual or possible relation of manifestation to consciousness. Alongside this fundamental sense, which has also passed into scientific language (phenomena of the corporeal world, “physical, chemical phenomena”), the term has assumed in philosophy further technical and determinate meanings.
In Aristotle, φαινόμενον is what appears to the senses, in opposition to being, “is,” the object of intellectual perception. This opposition between phenomenon and being, which in Aristotle is purely epistemological, had in Parmenides (q.V. ELEATISM) instead a strong ontological significance, inasmuch as in sensible appearances every consistency of objective reality was denied, being attributed only to the immobile and one Being. The reduction of phenomenon to the value of pure subjective experience is taken up again, with various tendencies, in modern philosophy, partially in the empiric nominalism of Berkeley (q.v.), for whom every sensible presentation is nothing other than an idea or representation of the spirit, and fully in the phenomenism (q.v.) of Hume, for whom the spiritual reality of the subject itself is posited only as conscious phenomenon. In Kant, phenomenon (Erscheinung) is “the object of possible experience in time within space,” that is, what presents itself in experience as the synthesis of sensible impressions or of the first intuitions of time and space. As such, the phenomenon is formally a construction of the subject or consciousness, and is opposed both to the pure matter of knowledge and to the thing in itself, unattainable by experience and thought. Kantian terminology decisively influenced the present philosophical meaning of the term: by phenomenon one generally understands today what presents itself to the subject in knowledge, as distinct from the thing in itself, and thus, as such, is not an immediate expression of an absolute reality transcending knowledge itself.
As is easily seen, this conception of phenomenon raises (and already raised in Kant) the question of the objectivity of experience and of knowledge in general. Once the split is introduced between the phenomenal appearances of reality and reality itself, the objectivity of knowledge is no longer an immediate position and must be otherwise founded through metaphysical-critical derivation. This is what post-Kantian critical philosophy attempted in various directions, but for the most part with negative results. In traditional philosophy, on the other hand, that split between reality and phenomenon is denied. The phenomenon is precisely the revealing, albeit partial and fragmentary, of reality in its contingent and dynamic values. Certainly, reality, encountering consciousness, is subjectively determined in its mode of being in knowledge, but this does not annul the radical objectivity of the phenomenal content, through which it remains possible for thought to attain the most interior and ontological values of the real.