In the twentieth century, the ghost of Spinoza continued to show itself, for example in the writings of Russell, Wittgenstein, Davidson, and Deleuze. By a logical contradiction, if something is non-contradictory, there is no reason that it should not exist.

For this reason, seventeenth-century texts on moral philosophy tend to be more akin to self-help books than to twenty-first century moral philosophy. touches the mind so little that the thing's presence moves the mind to imagining more what is not than what is. Still, his engagement with Spinozism is evident throughout his writings and attentive readers of his chief work may indeed note his ambivalence toward Spinoza's philosophy. For Spinoza, God or Nature—being one and the same thing—is the whole, infinite, eternal, necessarily existing, active system of the universe within which absolutely everything exists. However, if she thinks snakes are present, that fact serves to fuel her fear; and if she thinks them absent, her fear is greatly diminished.As Spinoza puts it: “For what constitutes the form of [such passions] is joy, or sadness, accompanied by an external cause… So if this is taken away, the form of love or hate is taken away at the same time. Spinoza considers how the affects, ungoverned, can torment people and make it impossible for mankind to live in harmony with one another. Since God had to exist with the nature he has, nothing that has happened could have been avoided, and if God has fixed a particular fate for a particular mode, there is no escaping it.

Steven Nadler, A Book Forged in Hell: Spinoza's Scandalous Treatise, Princeton University Press, 2011, ch. However, since non-human animals differ in nature from us, reason dictates that we “consider our own advantage, use them at our pleasure, and treat them as is most convenient for us” (ibid). In Spinoza’s view, the idea of an idea is not really distinct from the idea itself (E2p21s), so the clear and distinct idea we form of a passionate affect is not really distinct from that affect. However, as Kober (2013, 58–9) notes, one of the consequences of Spinoza’s views is that important conceptual tools of ecology lose their purchase. In the long run, Spinoza thinks, irrational affects will be forced to “accommodate themselves” more and more frequently to the rational affects.

Given that our greatest good is knowledge of God, ought we not all retreat to the mountaintop and spend our time in metaphysical inquiry? For this reason, Spinoza holds the prima facie surprising view that laws are morally binding on us even in cases in which those laws are not rational. However, many scholars (such as Garrett [1990, 229–30] and Nadler [2006, 219]) take this discussion of the free man to be Spinoza’s presentation of the model of human nature he promised in the preface to Ethics 4. Although virtue is founded in rational self-interest, rational self-interest in turn urges us to desire the good of others. W]e ought to think about and meditate frequently on the common wrongs of men, and how they may be warded off best by nobility.

For example, ‘E1p25’ refers to Ethics part 1 proposition 25; ‘E1p25d’ refers to the demonstration of that proposition; ‘E1p25s’ to its scholium; and ‘E1p125c’ to its corollary. Spinoza claims that whenever we “form a clear and distinct idea” of a passion, it will no longer be a passion (E5p3). Based on passages such as this, scholarship on Spinoza’s ethical theory has tended to depart from the traditional picture of imagination as something to be transcended through the use of reason; see, for example, Soyarslan (2014, 243–7), Steinberg (2014, 187–192) and James (2014, 154–159). Spinoza holds that everything that exists is part of nature, and everything in nature follows the same basic laws. The striving [ conatus] at issue is not to be confused with conscious effort, since Spinoza takes the principle to govern bodies as well as minds.In addition to providing etiological accounts intended to explain why people make the mistake of treating moral qualities as objective (and thereby to undermine the belief that they are objective), Spinoza develops two distinct arguments for his anti-realism. Each Attribute, however, expresses itself in its finite modes not immediately (or directly) but mediately (or indirectly), at least in the sense to be explained now. He thus subscribes to a desire-satisfaction theory of value: what is ultimately of value is the satisfaction of desire; things become valuable only by virtue of their being desired, or their serving to satisfy some desire. Since it often happens that a person wants something and later discovers it really to be undesirable — or even wants something in spite of the fact that he knows it to be undesirable — the distinction is an important one to preserve.