Phenomenology, metaphysical neutrality, and the essence-existence distinction
Husserl defined phenomenological research in his Logical Investigations as “metaphysically neutral” in the sense that it was indifferent to questions of existence. It is possible to engage in phenomenological research entirely apart from the question of the real existence of the thing being investigated. For example, it is possible to investigate material bodies phenomenologically while remaining uncommitted with respect to the real existence of any particular material body. In general, there is in phenomenology a mostly implicit but sometimes explicit distinction between givenness to consciousness and real existence. Givenness to consciousness is what accounts for the intentionality of consciousness even in those cases where the intentional object does not exist in reality (e.g., hallucinations or illusions).
It occurs to me that the possibility of metaphysical neutrality in phenomenological research is essentially a restatement of the medieval idea that there is a distinction between essence and existence. Thomas Aquinas notes in his De Ente et Essentia that it is possible to know what a thing is without knowing that it exists in actuality. So also for Edmund Husserl and the phenomenologists, it possible to engage in a phenomenological investigation of a thing while leaving to the side of the question of its real existence. More generally, Husserl notes in the Logical Investigations and Ideas I (for example) that the intentional object of a conscious act need not exist in reality. But the conscious act is no less intentional for all that, and it is always possible to investigate the “content” of the intentional object even granting that there is no guarantee that the object exists in actuality. The content is given while the actuality is presumed: this suggests, like Thomas Aquinas and others have suggested, that essence (“content”) and existence (actuality) are distinct.