beckderm Terence Kemp McKenna "Operating System" - Terence Kemp McKenna (November 16, 1946 April 3, 2000) was a writer, philosopher, psychonaut and ethnobotanist. He was noted for his knowledge of the use of psychedelic, plant-based entheogens, and subjects ranging from shamanism, the theoretical origins of human consciousness, and his concept of novelty theory. Terence McKenn..