There is a philosopher who, writing in Latin in a small house in The Hague in the seventeenth century, formulated one of the most radical worldviews Western philosophy has ever produced — and did so in the unlikely form of a treatise of geometry. That philosopher is Baruch (Bento) Spinoza (1632–1677), and the treatise is the Ethics demonstrated in geometrical order, published posthumously in the year of his death. In a little over two hundred pages, organized into definitions, axioms, propositions, and demonstrations, Spinoza proposes simultaneously a metaphysics of the absolute, a theory of human affects, a psychology of knowledge, and an ethics of freedom. His influence runs across three centuries — Lessing, Goethe, Hegel, Marx, Nietzsche, Deleuze, Antonio Damasio — and his name still functions, in the history of philosophy, as a cipher for an intellectual decision: thinking God, nature, and the human being as expressions of a single reality.

Life and context

Spinoza was born in Amsterdam in 1632, to a family of Sephardic Jews who had taken refuge from Iberian persecution. The community he belonged to lived in a peculiar situation: Dutch Protestants had granted these Jews a then-unparalleled tolerance, and the community prospered in international commerce and intellectual life, preserving Hebrew, Iberian Portuguese, and Castilian.

At twenty-three, in 1656, Spinoza was struck by the cherem — the most radical excommunication (herem) ever recorded in the archives of the Portuguese synagogue of Amsterdam. The formal reasons were not stated in the document, but involved his “horrendous heresies” and “monstrous deeds”. Spinoza had begun expressing, in conversation, positions that denied the immortality of the soul as dogma, the Mosaic authorship of the Pentateuch, and supernatural providence — theses he would later demonstrate geometrically.

Excommunicated, he changed his name (Hebrew Baruch → Latin Benedictus, all meaning “blessed”) and lived, until dying at 44 of pulmonary tuberculosis probably aggravated by the fine dust of the lenses he polished for a living, a life of remarkable intellectual austerity. He refused a chair at Heidelberg to preserve his freedom of thought. His relations with Leibniz, Christiaan Huygens, and Henry Oldenburg (secretary of the Royal Society) attest to the prestige he won during his life despite his status as a religious pariah.

The Ethics more geometrico

The geometrical form

The Ethics (in Latin Ethica ordine geometrico demonstrata) innovates radically in form. Inspired by Euclid’s Elements, Spinoza presents his metaphysics as a deductive chain: definitions, axioms, propositions, demonstrations, corollaries, scholia. The intent is not decorative: it is to show that fundamental truths about God, the human being, and happiness can be derived with the same rigor as mathematical truths — they do not depend on revelation, authority, or consensus.

The work is divided into five parts:

  • Part I: Of God
  • Part II: Of the nature and origin of the mind
  • Part III: Of the origin and nature of the affects
  • Part IV: Of human bondage, or of the force of the affects
  • Part V: Of the power of the intellect, or of human freedom

The opening of Part I

Part I begins with eight definitions, of which the most important is the third: “By substance I understand what is in itself and is conceived through itself: that is, that whose concept does not require the concept of another thing from which it must be formed.”

From this definition, Spinoza demonstrates, in a chain of propositions, his most famous thesis: there can only exist one single substance, and that substance has infinite attributes. It is cause of itself, infinite, eternal, indivisible. And this single substance, Spinoza calls — without irony, but with seismological effect for the theology of his time — God.

Deus sive Natura: the central thesis

The best-known formula of Spinoza’s philosophy is Deus, sive Natura — “God, that is, Nature”. The conjunction sive (that is, in other words) is not alternative: it is identification. For Spinoza, God and Nature are two designations for a single reality.

This identification was scandalous in its time and remains disorienting today. To understand it, two confusions must be dispelled:

It is not traditional theism: Spinoza’s God is not a personal, transcendent, creator, providential being, who chose to create the world and who can intervene in it through miracles. All of that is, for Spinoza, anthropomorphism — projection of our own finite categories onto the infinite.

It is not atheism: Spinoza’s God is not a negation of the divine, but a radical redefinition. It is infinite, self-sufficient reality, which expresses itself in everything that exists. The materialist atheist of the eighteenth century (La Mettrie, Holbach) would be, from the Spinozan standpoint, a mere inverted anthropomorphist — someone who inherits the concept of God from theology and negates precisely the God theology invented.

Spinoza further distinguishes Natura naturans (Nature naturing: the active infinite substance) and Natura naturata (Nature natured: the set of modes, that is, the finite things in which substance expresses itself). It is the same reality, seen from two angles: as productive activity and as production.

Attributes and modes

The single substance has infinite attributes. Each attribute is a form under which the essence of substance is expressed. Although the attributes are infinite, the human intellect knows only two:

  • Thought (cogitatio): the dimension under which the real expresses itself as ideas.
  • Extension (extensio): the dimension under which the real expresses itself as bodies in space.

This thesis resolves, in its own way, the problem of Cartesian dualism (mind vs. body): mind and body are not two separate substances that interact mysteriously, but two expressions — under distinct attributes — of the same reality. Every idea has a bodily correlate; every bodily state has a mental correlate. This is the thesis of psychophysical parallelism: “The order and connection of ideas is the same as the order and connection of things” (Ethics II, prop. 7).

Modes are finite things — a tree, an idea, a movement, an emotion. They are not self-sufficient substances: they are modifications of the single substance, ontologically dependent on it. A wave on the sea is a mode of the sea; a person is a mode of God-Nature.

Absolute determinism

The metaphysical consequence is shattering: everything that happens, happens by necessity. There is no real contingency, no free will, no free choice taken from nothing. Each thing follows from the whole according to necessary laws — just as, from a mathematical definition of triangle, it necessarily follows that the sum of its angles is two right angles.

Spinoza is not saying we are puppets: he is saying that freedom understood as “doing what one wants without being caused to do it” is a chimera. Everything that exists has a cause; what we call free will is, according to Spinoza, ignorance of the causes that determine us. When we act on desire, nothing seems to force us — but the desire itself has causes, and those causes have causes, in an indefinite chain.

The stone falling, he writes in a famous letter to Schuller (1674), if it had consciousness, would judge that it was falling freely. We are like that stone — with the difference that we can, through knowledge, understand the causes that move us.

Conatus: the striving to persevere in being

At the heart of Spinozan anthropology is the conatus: the striving by which each thing, insofar as it is in itself, perseveres in its being (Ethics III, prop. 6–7). The conatus is the universal dynamic principle — stones, trees, animals, and humans have conatus, each according to its nature.

In the human being, the conatus appears as:

  • Appetite (appetitus): the conatus referred jointly to mind and body.
  • Desire (cupiditas): the appetite with consciousness of itself.
  • Will (voluntas): the conatus as it refers only to the mind.

The thesis is radical: we do not desire things because they are good; we call them good because we desire them. Good and evil are not objective properties of things, but designations we project from our conatus. What increases our power of acting and existing, we call good; what decreases it, evil.

The affects

Part III of the Ethics is one of the greatest theories of the affects ever written. Spinoza begins by defining three primary affects:

  • Joy (laetitia): transition from lesser to greater perfection — increase in the power of acting.
  • Sadness (tristitia): transition from greater to lesser perfection — decrease in the power of acting.
  • Desire (cupiditas): conatus conscious of itself.

From these three, Spinoza geometrically derives the entire constellation of human affects: love (joy accompanied by the idea of an external cause), hatred (sadness accompanied by the idea of an external cause), hope, fear, jealousy, ambition, glory, pity, shame, repentance.

The decisive thesis: the affects are caused, not free. When we understand the causes that produce our affects, they cease to have over us the blind power they had; we can modulate our relation to them.

Bondage and freedom

Part IV — “Of human bondage” — describes the common condition of humans: we are subjected to affects whose causes we do not understand, we are dragged by passions in contradictory directions, we are unhappy. Ethics IV, prop. 4 formulates the sombre thesis: “It is impossible that the human being should not be a part of Nature, and that he should not undergo other changes besides those that can be understood through his nature alone.” There is no absolute autonomy: we are immersed in the infinite of natural causality.

But Part V — “Of the power of the intellect, or of human freedom” — proposes the way out. Freedom is not the absence of causes, but knowledge of causes. When I pass from the first kind of knowledge (imagination, hearsay, opinion) to the second (reason, adequate ideas of common properties) and to the third (scientia intuitiva, knowledge of the singular essence of things from the essence of God), passive affects are transformed into active affects. I remain caused, but by my own adequate ideas, not by the confused representations I receive from outside.

The summit is the intellectual love of God (amor intellectualis Dei): the joy that accompanies the idea of God as internal cause of my thinking. This love is eternal — it is the part of us that participates in the infinite. In one of the most discussed passages of Western philosophy, Spinoza writes: “We feel and experience that we are eternal” (V, prop. 23, scholium).

Politics and religion

Spinoza is not only a metaphysician. In the Theologico-Political Treatise (1670), published anonymously and soon banned, he formulates:

  • The separation between philosophy and theology: philosophy seeks truth, religion seeks obedience; each has its domain.
  • Freedom of thought as condition of a stable republic: “In a free republic, every man is permitted to think what he wants and to say what he thinks” (subtitle of the Treatise).
  • The historical critique of the Bible: Scripture is human text, written under determinate historical circumstances, and must be read by philological, not dogmatic method. Spinoza is, with Hobbes, founder of modern biblical criticism.

In the Political Treatise (posthumous, 1677, unfinished), he takes up themes of Machiavelli and Hobbes to defend a form of democracy: the regime most in accord with human nature, as it maximizes collective power.

Reception and influence

The eighteenth century treated Spinoza as enemy: “the atheist Spinoza” was a common epithet, and the term Spinozism functioned as accusation of immanentism and necessitarianism. The turn occurs at the end of the eighteenth century with the Pantheismusstreit (Pantheism controversy, 1785), when Jacobi denounced Lessing as a Spinozist and the entire cultured Germany was forced to take a position. Goethe, Herder, Schleiermacher embrace Spinoza. Hegel affirms that “to begin to philosophize is to begin with Spinoza”.

In the nineteenth century, Marx (radical immanence, without theology), Nietzsche (who recognized in Spinoza a “precursor” in a letter to Overbeck of 1881). In the twentieth century, Deleuze dedicates two books to Spinoza (Expressionism in Philosophy: Spinoza, 1968; Spinoza: Practical Philosophy, 1970). Antonio Damasio (Looking for Spinoza, 2003), neuroscientist, sees in the theory of the affects an anticipation of neuroscientific discoveries on emotion and cognition.

Why Spinoza still matters

We live in a culture in which the three fundamental Spinozan categories — God, Nature, Freedom — continue to be objects of public misunderstanding. Traditional theology declines, but religious vocabulary remains; naturalistic science proposes a universe regulated by laws, but hesitates to think the place of the human in that universe; we speak of freedom as if it were the first cause of our actions, even when neuroscience tells us otherwise.

Spinoza offered, 350 years ago, a synthesis: the real is one, its laws are accessible to reason, and freedom is lucid understanding of causes. To accept or to reject this synthesis is another matter — but to think against Spinoza requires thinking with Spinoza first. That is why he remains, in Hegel’s famous phrase, the philosopher “one cannot bypass”. One must pass through him.

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