He was perhaps one of the greatest philosophers who ever lived. A friend of humanity, wanting money only to give it to the poor, a friend also of animals, his heart was concerned only with the happiness of others; he believed that he could make the world happy by providing it with new pleasures, more beautiful fabrics, more beautiful colours, at a much lower price. … I have never seen a man with such a clear mind as his, with such erudition, especially in ancient history, as I have rarely found. He had been in all the countries of Europe, and I know of almost none, where he had not made long stays. He knew them all thoroughly, and had been often in Constantinople and Turkey. France, however, seemed to be the country he loved most.