“A hallucination is a fact, not an error; what is erroneous is a judgment based upon it.”

Welsh mathematician and philosopher

Bertrand Russell was a Welsh mathematician and philosopher, and a founder of analytic philosophy. He became one of the leading philosophers of the 20th century, known for work in logic, set theory, and the philosophy of language. He also helped bring philosophy to a wider public through his books and commentary. Outside academic philosophy, he was widely known for his outspoken atheism, pacifism, and opposition to nuclear weapons, and he often wrote on social and political questions.