6.]--undertakes to cure the unnatural and preposterous loves of his time, as one which he esteems of sovereign virtue, namely, that the public opinion condemns them; that the poets, and all other sorts of writers, relate horrible stories of them; a recipe, by virtue of which the most beautiful daughters no more allure their fathers' lust; nor brothers, of the finest shape and fashion, their sisters' desire; the very fables of Thyestes, OEdipus, and Macareus, having with the harmony of their song, infused this wholesome opinion and belief into the tender brains of children.

Chastity is, in truth, a great and shining virtue, and of which the utility is sufficiently known; but to treat of it, and to set it off in its true value, according to nature, is as hard as 'tis easy to do so according to custom, laws, and precepts.

The fundamental and universal reasons are of very obscure and difficult research, and our masters either lightly pass them over, or not daring so much as to touch them, precipitate themselves into the liberty and protection of custom, there puffing themselves out and triumphing to their heart's content: such as will not suffer themselves to be withdrawn from this original source, do yet commit a greater error, and subject themselves to wild opinions; witness Chrysippus,--[Sextus Empiricus, Pyyrhon.

Hypotyp., i.
14.]--who, in so many of his writings, has strewed the little account he made of incestuous conjunctions, committed with how near relations soever.
Whoever would disengage himself from this violent prejudice of custom, would find several things received with absolute and undoubting opinion, that have no other support than the hoary head and rivelled face of ancient usage.

But the mask taken off, and things being referred to the decision of truth and reason, he will find his judgment as it were altogether overthrown, and yet restored to a much more sure estate.