 So far we have seen that, for Leibniz, the human good consists in the lasting state of pleasure that accompanies moral perfection.  Moral perfection, in turn, is cultivated through the perpetual pursuit and acquisition of knowledge of the perfection of others, the universe, and God. Although all knowledge contributes to moral perfection and is therefore practical in a broad sense of the term, ethics nevertheless is a distinct branch of science, capable of the same level of demonstrative rigor as arithmetic and geometry (NE, Preface, p. 50; PW, “Meditation on the Common Concept of Justice,” pp. 49–50). Leibniz shares this view of ethics with other important seventeenth-century thinkers, such as Hobbes (1588–1679), Spinoza (1632–1677), and Locke (1632–1704). And although Leibniz never wrote a comprehensive ethical treatise in the geometrical style, it is clear from what he left us that, in addition to a naturalistic-metaphysical theory of the good, ethical science also includes a science of natural law. 