William Kingdon Clifford was a British mathematician and philosopher born in 1845. He is best known for his work in the fields of geometry and mathematical logic. Clifford contributed to the development of Clifford algebras, which are important in various areas of mathematics and physics, particularly in quantum mechanics and theory of relativity. In addition to his mathematical achievements, Clifford was also a prominent advocate for scientific rationalism and the philosophy of empiricism. He famously argued that beliefs should be based on evidence and that it is wrong to hold beliefs without sufficient justification. His ideas have influenced both philosophy and science, making him a significant figure in both fields.