WorkBaruch Spinoza

The Principles of Descartes' Philosophy, with Metaphysical Thoughts

The only book Spinoza published under his own name — a geometrical exposition of Descartes, written for a pupil, with an appendix where his own philosophy begins to show through.

by Baruch Spinoza243 passages held

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Original title: Renati Descartes Principiorum Philosophiae pars I et II, more geometrico demonstrata / Cogitata Metaphysica
First published: 1663(aged 31)
Original language: Latin

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Overview

A young Leiden student, Johannes Casearius, came to Spinoza to learn Descartes. To teach him without simply handing over his own unorthodox opinions, Spinoza recast the first two parts of Descartes's Principles of Philosophy in strict geometrical order — definitions, axioms, propositions, proofs. His friends in Amsterdam saw the manuscript, urged him to complete and publish it, and in 1663 it appeared as Renati Des Cartes Principiorum Philosophiae Pars I et II, more geometrico demonstrata. It was the only book Spinoza ever published under his own name. His friend Lodewijk Meyer supplied the preface and made the essential warning explicit: the author is expounding Descartes, not endorsing him, and dissents from several of the very propositions he here proves. Appended to it was a short original piece, the Cogitata Metaphysica — Metaphysical Thoughts — dressed as a handbook of scholastic metaphysics but quietly threaded with positions that were Spinoza's own and not Descartes's at all, so that a careful reader could see where the expositor was heading. The book earned Spinoza a modest public standing as a sharp interpreter of Descartes, the only such recognition he would receive in life; everything else he wrote he published anonymously or withheld for after his death. For later scholars it became the one dated, authorized text against which to read a body of work that otherwise reaches us unsigned or posthumous.

Key concepts

What is 'clear and distinct perception'?

It is Descartes's test of truth, and the book's foundation: whatever the mind perceives clearly and distinctly is true. Spinoza expounds how Descartes reaches it — sweep away everything the least doubt can touch, arrive at the one thing doubt cannot, 'I think, I am,' and read off from its self-evidence the mark that certifies all further knowledge. To follow the proofs you must hold this criterion; every demonstration leans on it.

What do 'objective' and 'formal' reality mean in the God proof?

These scholastic terms carry Descartes's proof of God, which the book sets out in strict order. The 'objective reality' of an idea is the reality of the thing as represented in the mind; its 'formal reality' is the reality it has as an actually existing thing. Descartes argues our idea of an infinite God holds so much objective reality that only an actually infinite being could have caused it. Miss the pair and the central proof stays opaque.

What are the 'created eternal truths'?

Descartes held that even the eternal truths — that twice two is four, that a triangle's angles sum as they do — were freely established by God's will, and could have been made otherwise. The book proves this Cartesian doctrine faithfully; yet it is exactly where Spinoza's own view, that nothing in God is arbitrary will, presses against the text. Watching him expound what he cannot believe is much of the book's interest.

How does the Cogitata Metaphysica sort the kinds of 'being'?

It opens by dividing what we call being. Real being is a thing existing outside the mind; a being of reason (ens rationis) is a mode of thinking — genus, species, time, number — that helps us compare things but names nothing real; a being of the imagination is a mere chimera. Keeping these apart, Spinoza shows, dissolves a crowd of metaphysical puzzles bred by treating aids to thought as real things.

What is Descartes's physics that Part II lays out?

Its core is that the essence of body is simply extension — being spread out in length, breadth, and depth. From this a vacuum is impossible, since empty space would be extension with nothing extended, a contradiction; and motion is nothing but a body's transfer from the neighborhood of one set of bodies to another. This mechanical world of matter-as-geometry is what the geometrical method here describes.

Themes of the book

What this book returns to, gathered into themes and ordered by how much of the text each one occupies.

Descartes proved, and quietly exceeded

Can another man's philosophy be set out in strict geometrical order without being endorsed — and what shows through when Spinoza does the setting out? The exposition is faithful; the appendix is not innocent.

Written to teach a pupil Descartes without handing over his own opinions, Spinoza recast the first two parts of the Principles — physics, motion, and mechanics included — into definitions, axioms, and proofs, with Meyer's preface warning that the author expounds Descartes and dissents from much he here demonstrates. The appended Cogitata Metaphysica, dressed as a scholastic handbook, threads in positions that are Spinoza's own. The only book he published under his own name, it became the one dated, authorised text against which to read the rest.

metaphysics
epistemology
motion
mechanics
physics
ontology
logic
matter
substance
extension
force
geometry
existence
essence
perfection
eternity
creation
divine attributes
god
certainty
necessity
truth
error
time
infinity
will
causation
free will

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Within this work

passages held: 243
distinct concepts: 211
by passages held, corpus-wide: #115

What this book thinks together

Every arc around the wheel is one concept in this book. A ribbon joins two the text reaches for together, and its width is how many of its passages hold both. Strongest: motion with physics.

Concept co-occurrence, strongest first 8 concepts, joined by 17 pairings. 92 shared passages in all. 83 weaker pairings reach beyond these concepts and are not drawn.
Concept	Paired concept	Shared passages
motion	physics	13
metaphysics	ontology	11
epistemology	logic	10
mechanics	motion	8
causality	metaphysics	7
mechanics	physics	6
logic	ontology	5
causality	mechanics	4
causality	ontology	4
logic	metaphysics	4
causality	epistemology	3
causality	logic	3
causality	physics	3
epistemology	metaphysics	3
epistemology	ontology	3
logic	motion	3
causality	motion	2

Works held

The author's work in order, this book marked in place. Your-language title first, the original beneath it where the two differ; side chips show which full texts are held.

1663 The Principles of Descartes' Philosophy, with Metaphysical Thoughts (Renati Descartes Principiorum Philosophiae pars I et II, more geometrico demonstrata / Cogitata Metaphysica) you are here LAEN
1670 A Theologico-Political Treatise (Tractatus Theologico-Politicus)
Written in the years around 1670 to defend Dutch toleration and answer the Calvinist clergy, it was the one polemic Spinoza put into print — and its scandal is much of why the Ethics waited until after his death.
LAEN
1677 A Political Treatise (Tractatus Politicus)
Spinoza's last work, and the only one he wrote as a practical manual of governing; he was still at it, on the chapter about democracy, when he died in 1677.
LAEN
1677 Ethics, Demonstrated in Geometrical Order (Ethica Ordine Geometrico Demonstrata)
The work the others point toward: the finished system Spinoza spent some fifteen years building and never dared publish, where his God, his psychology, and his account of freedom are proved as a single chain of reasoning.
LAEN
1677 The Correspondence of Spinoza (Epistolae)
The nearest thing to a notebook Spinoza left: his exchanges with scientists, critics, and friends, printed among his posthumous works with the private matter cut out by wary editors.
LAEN
1677 Treatise on the Emendation of the Intellect (Tractatus de Intellectus Emendatione)
Before the Ethics found its geometrical form, Spinoza sketched its theory of knowledge here and then abandoned the draft — one of his earliest surviving works, and one he left unfinished.
LAEN
1862 Short Treatise on God, Man and His Well-Being (Korte Verhandeling van God, de Mensch en deszelfs Welstand)
Composed around 1660 and shown only to Spinoza's friends, it is his earliest systematic work — the seed of the Ethics, and it stayed unpublished until a manuscript surfaced in the nineteenth century.
NLEN

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