Spinoza's Ethics

A brief discussion of how to read Spinoza’s masterpiece, the Ethics.

1 Background

Bento (in Hebrew, Baruch; in Latin, Benedictus: all three names mean “blessed”) Spinoza (1632-1677) was born in Amsterdam and died in The Hague. He was born into a community of Portuguese Jews that had settled in the city of Amsterdam in the wake of the Portuguese Inquisition (1536), which had resulted in forced conversions and expulsions from the Iberian peninsula. His father, Miguel de Espinoza, was a successful, though not particularly wealthy, merchant.

Though Spinoza had a traditional and devout Jewish upbringing his relationship to Judaism was complex, and he was ultimately excommunicated on 27 July 1656, from the Jewish church, on the basis of his philosophical works (he was at this time only 23). While it is not exactly clear which doctrines in particular were the basis for the excommunication, it would likely have been due to several doctrines that he denied, including the immortality of the soul; the notion of a transcendent, providential God—the God of Abraham, Isaac and Jacob; and that the Law was neither literally given by God nor binding on Jews (see (Nadler 2016)).

The Ethics was not published until after Spinoza died, in 1677, though there is some evidence that it was ready to be published at least as early as 1675. Writing to his friend Oldenberg Spinoza says,

a rumor was spread everywhere that a book of mine about god was in the press, and that in it I strove to show that there is no God. Many people believed this rumor. So certain theologians-who had, perhaps, started the rumor themselves–seized this opportunityto complain about me to the Prince and the magistrates. Moreover, the stupid Cartesians, who are thought to favor me, would not stop trying to remove this suspicion from themselves by denouncing my opinions and writings everywhere. When I learned this from certain trustworthy men, who also told me the theologians were everywhere plotting against me, I decided to put off the publication I was planning until I saw how the matter would turn out. (Letter 68, IV/299; quoted in (Curley 1994))

Spinoza died about a year and a half after this—on 21 February, 1677—of a lung disease that was possibly due to the dust of the lenses he had been grinding in order to support himself. He was only 44. A few months later his friends arranged for the publication of the Ethics, along with his correspondence and three other unfinished works: the Treatise on the Emendation of the Intellect, the Political Treatise, and a Hebrew Grammar.

Since the Ethics is an extraordinarily rich work, our discussion will not be adequate to the topics it covers, nor the depth of detail that they warrant. Instead we will look at just a few of the central arguments for each part of the Ethics. In this first set of notes we look at just one of Book I’s central arguments—the argument that there is only one substance or thing and that this substance is God, understood as the totality of nature.

2 The Geometric Method

Before we turn to the arguments of the Ethics, it’s worth commenting on the nature of the method Spinoza follows in the overall argument of the Ethics. This method is what is known as the “geometric method” in that it follows a form of presentation most famously executed by Euclid in his Elements. It thus shares with that work a presentation of argument in terms of definitions, axioms, propositions and demonstrations. There are at least two important reasons for Spinoza’s choice of the geometric method for the presentation of his philosophy.

First, the method allows the reader to connect and cross-reference each demonstrated proposition with earlier definitions, axioms, etc., from which it is derived. In this it is meant to be a precise and logically well-grounded presentation of Spinoza’s views (though in actuality it is not always clear that Spinoza’s conclusions follow from the definitions and axioms to which he appeals). Second, the geometric method is also meant to embody a kind of development in the thinking of the reader; as the reader moves through the various initial definitions, axioms, and demonstrations, the activity of doing this manifests a kind of development in the reader’s understanding of the nature of things.

As with Euclid’s Elements, Spinoza’s Ethics proceeds with seven kinds of claim:

meanings of key terms
basic, self-evident truths
the points that Spinoza explicitly argues for by means of “demonstrations”
propositions that follow directly from the propositions they are appended to
propositions specifically for demonstrating truths related to some further proposition; Spinoza reserves them for propositions related to physical bodies (these appear only in Part II)
propositions that are assumed as true even if not self-evidently true; Spinoza uses these with respect to assumptions about the human body that are drawn from (and apparently, justitifed by) “common experience”
explanatory remarks on the propositions; these are some of the places where Spinoza engages in more informal explanation and elucidation


Curley, E. M. 1994. “Introduction.” In A Spinoza Reader: The Ethics and Other Works, ix-xxv. Princeton, N.J: Princeton University Press.
Nadler, Steven. 2016. “Baruch Spinoza.” https://plato.stanford.edu/archives/fall2016/entries/spinoza.