Psychedelic experiences can be understood as a form of fantasy activity, offering a favorable situation for phenomenological research. Applying Merleau-Ponty's later conceptual framework from The Visible and the Invisible, along with his mescaline analyses from The Phenomenology of Perception, psychedelic visions and emotional states are discussed within the Merleau-Pontian framework of the 'wild world.' From a phenomenological viewpoint, psychedelic visions represent an ongoing sense-making and Gestalt-formation process in which the subject's elaborative activity plays a crucial role.
After Romanticism, 19th-century thought regarded dreams as a denial of reality. Freud and later Binswanger, in different ways, attributed a primary role to dreams over waking thought. Freud saw the dream as hallucinatory wish-fulfillment, while Binswanger viewed it as a representation of existence. Binswanger was significantly inspired by Being and Time in formulating his dream theory. However, in Being and Time, Heidegger describes the waking modes of Dasein, and even the later Heidegger did not engage with dreams. In the Andenken texts, references to dreams and shadows appear not as dreams but as metaphors for Dasein's waking mode.