Summary: Ethics (page 8)

It is therefore incorrect to believe that nature is either perfect or imperfect, since it does not aim at any goal; the notions of perfection and imperfection are merely fictions introduced by human beings.

Similarly, good and evil do not signify anything positive in things but are merely modes of thinking, notions that we derive from comparing things with one another ¹.

Nevertheless, we must retain these terms in order to form an idea of human nature.

For this reason, Spinoza begins Part IV by defining moral concepts as follows: By good and evil, I shall mean what we know with certainty to be a means of approaching or departing from the model of human nature that we set for ourselves ².

As a result, the notion of good carries no other meaning than that of utility: By good, I shall mean that which we know with certainty to be useful to us ³. Or, more broadly, that which benefits us:

We call good or evil that which serves or harms the preservation of our being ⁴.

Finally, Spinoza links the notions of good and evil to those of joy and sadness, as defined in the previous book—namely, as a passage to greater or lesser perfection: The knowledge of good and evil is nothing other than the affect of joy or sadness, insofar as we are conscious of it ⁵.

It is in Proposition 4 of this part that we find Spinoza’s famous assimilation of God to nature: [...] the very power of God, in other words, of Nature ⁶ (Deus sive natura).

Human servitude arises from the fact that, due to determinism, we cannot control or escape an affect by an act of will alone. In reality, an affect can only be thwarted or suppressed by an opposing affect that is stronger than the affect to be thwarted ⁷.

Spinoza formulates several psychological propositions to explain how affects take hold of us. For example: An affect related to something we imagine to be necessary is, all things being equal, more intense than an affect related to something possible or contingent—that is, something not necessary ⁸.

From Proposition 18, Spinoza announces that he will now demonstrate what reason prescribes—namely, which affects align with the rules of human reason and which, on the contrary, are contrary to them ⁹.

He asserts that reason demands nothing that is against nature. Reason itself demands that each person love themselves, seek what is useful to them, aspire to everything that increases their perfection, and strive, as far as possible, to preserve their being ¹⁰.

Spinoza defines virtue as acting according to the proper laws of one’s nature. Thus, the foundation of virtue is the very effort to conserve one’s proper being ¹¹.

What is most useful to us is that which shares our nature. Therefore: To man, nothing is more useful than man ¹². As a result, a person governed by reason—that is, someone who seeks their own happiness—naturally aspires to nothing other than the general happiness of humankind.

Spinoza thus challenges the idea that acting virtuously means acting selflessly. One might even say that properly understood, egoism is the foundation of altruism, since others are fundamentally useful to us.

If we all lived under the guidance of reason, each person would act according to the sovereign right of nature—that is, they would do all that follows necessarily from their own nature. However, because of the affects, which surpass human power or virtue, people find themselves driven diversely, contrary to one another ¹³.

¹ ibid.
² ibid.
³ IV, definition 1
⁴ IV, prop. 8, demonstration
⁵ ibid.
⁶ IV, prop.4
⁷ IV, prop.7
⁸ IV, prop.11
⁹ IV, prop.18, note
¹⁰ ibid.
¹¹ ibid.
¹² IV, prop.35, corollary 1
¹³ IV, prop.37, note 2