In this paper we discuss the definitional problems of altered states of consciousness and their potential relevance in phenomenological investigation. We suggest that visionary states or visionary phantasy working induced by psychedelics, as extraordinary types of altered states, are appropriate subjects for phenomenological analysis. Naturally, visionary states are not quite ordinary workings of the human mind, however certain cognitive psychological and evolutionary epistemological investigations show that they can give new insights into the nature of consciousness. Furthermore, we suggest that contemporary (...) inquiries concerning altered states in consciousness studies give an opportunity to complete the contemporary phenomenological investigations of phantasy with the notion of visionary phantasy. Here we propose that the similarities and differences between Dieter Lohmar’s weak phantasy and Benny Shanon’s concept of vision are precisely discernible, and, consequently, it may be possible that weak phantasy and visionary phantasy are situated on the two outermost poles of the colorful spectrum of phantasy activity. (shrink)