Complex sentence: Timothy Francis Leary (October 22,1920--May 31,1996) was an American psychologist, philosopher, and writer known for advocating the exploration of the therapeutic potential of psychedelic drugs under controlled conditions.
Split into simpler sentences: Timothy Francis Leary (October 22,1920--May 31,1996) was an American psychologist. He was also a self-described philosopher, and writer known for advocating the exploration of the therapeutic potential of psychedelic drugs under controlled conditions.