Baruch de Spinoza (1632-1677) was expelled from the Jewish community of Amsterdam because he thought something the community could not think: that God is not a being standing opposite the world, but the world itself. The excommunication of 1656 was so radical that no one was permitted to speak with him, stand near him, or read his writings. Spinoza continued to grind lenses and wrote a book he did not publish in his lifetime. The Ethics, Demonstrated in Geometrical Order (1677) appeared only after his death. In it lies a thought that has not been silenced since: Deus sive Natura — God or Nature.
#One Substance, Infinitely Many Expressions
What Spinoza unfolds in the Ethics begins with a single claim: there is only one substance. This substance is infinite, exists necessarily out of itself, and expresses itself in infinitely many attributes, of which we recognise two: extension and thought. Everything particular — every body, every thought, every thing — is not an independent being but a mode, a determinate way in which the one substance expresses itself.
This position, substance monism, is directed against Rene Descartes (1596-1650), who had split reality into two separate substances: res cogitans (thinking thing) and res extensa (extended thing). If you take Descartes seriously, you face an insoluble problem: how can two substances interact that have nothing in common? The mind would have to act on the body and vice versa, yet two essentially different substances have no point of contact. Descartes’ makeshift solution — the pineal gland — was consistently named by Jochen Kirchhoff (1944-2025) in his lectures for what it is: a fantasy born from the embarrassment of a false starting point (cf. Kirchhoff, 2006). Spinoza sidesteps the problem by dissolving the dualism. Mind and body are not two things but two perspectives on the same thing.
#Conatus: The Striving in Being
In Part Three of the Ethics, Spinoza articulates a proposition that works like a bridge between rationalist metaphysics and living experience: every thing, insofar as it lies within it, strives to persist in its being. This striving he calls conatus. It is not a conscious intention but the basic principle of all existence. A stone does not fall because it wants to. But it behaves according to its nature. A person does not think because they decide to think. But the mind strives to increase its power of acting, just as the body strives to preserve itself.
What Spinoza describes here bears a kinship with what appears in Jochen Kirchhoff’s natural philosophy as Bewusstwerdungsdrang — an urge toward awareness: a striving that inheres in reality itself, not one first imported by the subject. The difference is that Spinoza’s conatus remains a principle within a closed system, while Kirchhoff’s drive toward awareness points toward an open, living whole that unfolds and intensifies out of itself (cf. Kirchhoff, 1998). Spinoza describes the striving; Kirchhoff describes the growth. These are not the same.
#Amor Dei Intellectualis — and the Question of Knowledge
In Part Five of the Ethics, Spinoza’s thought reaches its summit. He describes three kinds of knowledge: unreliable sense experience, ordering reason, and finally scientia intuitiva, which grasps the particular immediately within the whole. From this third kind springs what Spinoza calls amor dei intellectualis: the intellectual love of God, which is simultaneously the love with which God loves himself.
Here Spinoza touches an experience that reaches far beyond rationalism. If you take in the Ethics with your whole body and not only with your understanding, something can happen: the rhythm of your breathing changes, a deep concentration arises, the mind becomes still and wide at once. There are experiences that ignite at Spinoza’s thinking and that connect with something real in what he calls scientia intuitiva: a knowing that is no longer a standing-opposite but a participating.
And yet a contradiction remains. Spinoza describes this highest knowledge in the language of geometric demonstration: definitions, axioms, propositions, proofs. Jochen Kirchhoff named this contradiction in conversation: Spinoza, although a great mind and also a spiritual one, expresses himself in a language that does not do justice to what he wants to say (cf. Kirchhoff, 2023). The geometric method is a vessel that freezes its content. What is meant as living knowledge becomes a theorem. What is meant as love becomes a proposition.
#Goethe, Einstein, and the Spinoza Effect
Spinoza’s influence on German intellectual history can hardly be overstated. Goethe was a Spinozist before he encountered Schelling’s natural philosophy. What fascinated him about Spinoza was the unity of God and nature, the rejection of any creator-god standing opposite the world. Einstein admired Spinoza throughout his life and repeatedly declared that his concept of God was Spinoza’s: a cosmic order that is neither personal nor arbitrary but manifests itself in the lawfulness of nature.
But precisely the question of what Spinoza’s Deus sive Natura actually means is where the traditions diverge. When you think Deus sive Natura, the question immediately arises: is nature then God? Or is God then nature? For the materialist, God dissolves into nature, and what remains is a world without interiority. For natural philosophy, nature dissolves into something more encompassing that includes mind, consciousness, and aliveness. Spinoza stands at the fork. He dissolved the dualism, but he did not decide in which direction the dissolution leads.
Schelling, in his Naturphilosophie (1797), makes this decision. Nature is not merely a substance with attributes. It is a living process in which mind and matter mutually bring forth one another. “Nature should be the visible spirit, spirit the invisible nature” (cf. Schelling, 1797). What remains a logical identity in Spinoza — God is nature — becomes in Schelling a dynamic unity: nature becomes spirit, spirit becomes nature.
#What Spinoza Opens and What He Closes
Spinoza’s thinking stands closer to the truth than any materialism and closer than any dualism. Deus sive Natura is a more honest formula than the claim that dead matter somehow produced consciousness. If you read Spinoza, you understand why the split between mind and body is a mistake: not a problem to be solved, but a question wrongly posed. In this respect, Spinoza belongs to the line running from Giordano Bruno through Schelling to Kirchhoff.
But Spinoza’s substance is silent. It does not work from within like Bruno’s inner artist. It does not shape, unfold, or grow. It is everything there is, yet it has no voice. The geometric method Spinoza chooses expresses this silence: reality is deduced, not heard. The living cosmos, as natural philosophy conceives it, cannot be proved. It can be experienced.
If you are interested in the philosophical background of the mind-body problem that Spinoza tried to solve, or in the epistemology that follows from his third kind of knowledge, you will find the continuation in those entries.