Alexander Graham Cairns-Smith FRSE was an organic chemist and molecular biologist at the University of Glasgow. He was most famous for his controversial 1985 book 'Seven Clues to the Origin of Life. The book popularized a hypothesis he began to develop in the mid-1960s—that self-replication of clay crystals in solution might provide a simple intermediate step between biologically inert matter and organic life. He inspired other ideas about chemical evolution, including the Miller–Urey experiment and the RNA World, all of which are hypotheses that have played important roles in attempts to understand the origin of life.
Cairns-Smith also published on the evolution of consciousness, in 'Evolving the Mind' (1996), favoring a role for quantum mechanics in human thought.