Yes, there is a continuum of thought on the matter. I use the following,rough scale, which can be adapted to any branch of phenomenonology: Knowers: those who have had personal experience to establish the existence of the phenomenon beyond all doubt ("I know BF exists because I saw one and am absolutely certain of what I saw.") Proponents: those who have either had personal experience or are sufficiently convinced by the evidence currently on proffer but who entertain some doubt ("I am reason