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Primary sourceBook1677 (written 1661-1675)

Ethics

Benedictus de Spinoza · 1677 (written 1661-1675)

Spinoza's masterwork of philosophy, laid out as geometric proofs, arguing that God and Nature are one and exploring human emotion and freedom.

This is Spinoza's own philosophical masterwork, the core text defining his ideas on God, mind and freedom.

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Title page of Spinoza's Ethica in Latin. Large capital letters read ETHICA, followed by 'Ordine Geometrico demonstrata, ET In quinque Partes distincta, in quibus agitur', then a list of five parts numbered I to V with Latin titles.
Benedictus de Spinoza, Ethica, published 1677 (written 1661-1675).

About this source

What it is

The Ethics is a philosophical treatise written in Latin by Benedictus de Spinoza, composed between 1661 and 1675 and published only after his death in 1677. It is structured like a geometry textbook, building definitions and axioms into proofs about God, the mind, the emotions and human freedom.

Why it matters

The book argues that God is identical with Nature itself, rejecting the idea of a God who stands outside the universe and acts by free will. It also claims mind and body are two ways of describing one thing, challenging Descartes. These were radical, controversial ideas in Spinoza's time and shaped later philosophy.

Look closer

  • Why might a philosopher choose to write about God and emotions using geometric proofs instead of ordinary prose?
  • What does the title page tell you about how the work was organised?
  • Why do you think this book was published only after Spinoza's death?

This book is part of the curated material that grounds the AI version of Baruch Spinoza on Humy.ai — when students ask about related events, the AI can quote it and cite it.

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Title page of the Tractatus Theologico-Politicus, printed in black letter-style serif type with a handwritten inscription 'Auctore Benedicto de Spinoza' and an ornamental woodcut at the bottom, imprint reading Hamburgi, Apud Henricum Kuhrabt, 1670.Book

Primary source

Tractatus Theologico-Politicus

Benedictus de Spinoza · 1670

Oil painting of a man with long dark curly hair, wearing a dark coat and a large white collar, against a dark brown background. He looks toward the viewer with a calm expression.Painting

Primary source

Portrait of Benedictus de Spinoza

Unknown · c. 1665

Title page of a book. At top: 'B. D. S.' Large capitals below read 'OPERA POSTHUMA,' followed by italic Latin text 'Quorum series post Praefationem exhibetur.' A small woodcut ornament of fruit and ribbons sits in the middle, and at the bottom is the date 'MDCLXXVII' written as 'CIO IC CLXXVII' style Roman numerals.Book

Primary source

Opera Posthuma

Benedictus de Spinoza · 1677

Title page of a 1677 book in Latin. Large capitals read EPISTOLAE, followed by DOCTORUM QUORUNDAM VIRORUM, AD B. D. S. ET AUCTORIS RESPONSIONES, and a line about elucidating other works. Faded text from another page shows through in the background.Letter

Primary source

Epistolae, Correspondence of Benedict de Spinoza

Benedictus de Spinoza · 1661-1676, published 1677

Open handwritten manuscript on aged, browned paper with ink text in dense cursive lines across both pages, the left page torn at its upper and lower edges. Text is in Latin script, with bold headings and marginal notes.Document

Primary source

Vatican Manuscript of Spinoza's Ethics

Pieter van Gent (copyist), after Benedictus de Spinoza · c. 1675

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