G. E. Moore was a British philosopher born in 1873, known for his significant contributions to the field of analytic philosophy. He is best recognized for his work in ethics and epistemology, particularly for his defense of common sense and the idea that certain truths are self-evident. His famous "open question argument" challenged the notion that moral properties could be reduced to natural properties. Moore was also a prominent figure in the early 20th-century philosophical movement, influencing many thinkers, including Bertrand Russell and Ludwig Wittgenstein. He served as a professor at University College London and published several important works, including "Principia Ethica" in 1903, which laid the groundwork for modern ethical theory.