Wherein the False Notions of Machiavel, Hobbes, Spinoza, and Mr. Bayle, as They are Collected and Digested by the Author of The Fable of the Bees, are Examin'd and Confuted; and the Eternal and Unalterable Nature of Moral Virtue is Stated and Vindicated. To which is Prefix'd, a Prefatory Introduction, in a Letter to that Author