Jeremy Bentham. Was born in 1748 and was a leading theorist in Anglo-American philosophy of law, and a political radical whose ideas influenced the development of welfarism.
He advocated individual and economic freedoms, the separation of church and state, freedom of expression, equal rights for women, the right to divorce, and (in an unpublished essay) the decriminalising of homosexual acts. He called for the abolition of slavery, capital punishment, and physical punishment, including that of children. He has also become known as an early advocate of animal rights.
Hundreds of years ahead of his time and did a lot of good.