Last-born son of a lawyer who fathered twenty children, Arnauld became a theologian, logician and philosopher. He collaborated with both Nicole and Pascal on their famous The Art of Thinking, which later became known as ‘the Port Royal Logic’ or sometimes just ‘The Logic’. He is also remembered for authoring several of the replies to Descartes’ Meditations on First Philosophy, gaining in the process a reputation as an intellectually rigourous and perceptive critic, and bringing attention to the problem now known as
