These are still the opinions of orthodox Confucianists, but at different times scholars have arisen, who from their own experiences in the world, have come to conclusions diametrically opposed to those taught by the Sage. In their opinion the Psalmist was right when he said, "The heart of man is deceitful above all things and desperately wicked." Scarcely had Confucius been gathered to his fathers when the Philosopher Hsuen enunciated this view, and since then the doctrine has formed the chief ground of contention among all schools of philosophy down to the present day. By certain writers it has been held that in man's nature there is a mixture of good and evil, and by no one was this view more ably expounded than by the philosopher Chu Hi (A.D. 1130-1200). In season and out of season this great writer, who has done more than any one else to elucidate the dark pages of the classics, "taught that good and evil were present in the heart of every man, and that just as in nature a duality of powers is necessary to the existence of nature itself, so good and evil are inseparably present in the heart of every human being." But there were others who felt that the bald and conventional system proclaimed by Confucius was insufficient to satisfy the desire for the supernatural which is implanted in men of every race and of every clime, and then at once a school arose, headed by Laotz[)u] (sixth century B. C.), the Old Philosopher; which, adopting the spirit of Brahminism, taught its sectaries to seek by self-abnegation freedom from the entanglements of the world, and a final absorption into the Deity. The minds of most Chinamen are not attuned to the apprehension of philosophical subtleties, and the wisdom imparted by Laotz[)u] to his countrymen in the pages of his 'Taote King' (The Book of Reason and Virtue), soon became debased into a superstitious system by a succession of charlatans, who, adopting Laotz[)u]'s doctrine that death was only another form of life, taught their followers to seek to prolong the pleasures of the present state of existence by searching in the mazes of alchemy for the elixir of life and the philosopher's stone. Before the faith reached this degraded position, however, several writers supplemented and enlarged on the doctrines advanced by Laotz[)u]. Foremost among these were Litz[)u] and Chwangtz[)u], who were both men of great metaphysical ability, and whose speculations, though not always in harmony with those of their great master, help to some extent to elucidate his system and certainly add considerable interest to it.