A.J. Ayer was a British philosopher known for his work in the field of logical positivism, a movement that emphasized the importance of empirical evidence and logical reasoning. Born in 1910, he became a prominent figure in 20th-century philosophy, particularly through his influential book, Language, Truth and Logic, published in 1936. Ayer argued that many philosophical questions are meaningless if they cannot be tested or verified through experience. Ayer was also a professor at University College London and later at Oxford University. He contributed to discussions on ethics, language, and the philosophy of science. His ideas helped shape modern philosophy, particularly in the areas of analytic philosophy and empiricism. Ayer passed away in 1989, leaving a lasting impact on philosophical thought.