Psychedelic science is a field of research that explores the effects and potential therapeutic uses of psychedelic substances. These substances, such as LSD, psilocybin, and DMT, have the ability to profoundly alter one's sense of reality and self, as explained by Dr. Matthew Johnson. The science involves understanding the pharmacology of these substances, particularly their interaction with the serotonin 2A receptor in the brain, as discussed with Dr. Robin Carhart-Harris. It also involves studying the subjective experiences or phenomenology associated with these substances. Furthermore, psychedelic science is exploring the potential of these substances in treating mental health conditions like depression, although this is a topic of ongoing debate and research.