Hilary Putnam was an American philosopher and mathematician, renowned for his work in philosophy of mind, philosophy of language, and philosophy of science.
Peter Geach was a renowned British philosopher and logician, known for his extensive contributions to the fields of linguistics, philosophy of language, and logic.
G.E. Moore was an influential British philosopher known for his contributions to ethics, metaphysics, and epistemology.
Rudolf Carnap was a German philosopher known for his significant contributions to logic, philosophy of science, and linguistic analysis.