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Thoughts on the True Estimation of Living Forces

Immanuel Kant · 1749

Kant's first published work (1749), where he tried to settle the dispute over living forces between followers of Descartes and Leibniz.

This was Kant's first published work, showing his earliest contribution to natural philosophy.

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Title page of a German book in black-letter (Fraktur) type on aged paper. Title reads Gedanken von der wahren Schätzung der lebendigen Kräfte, with further text naming Immanuel Kant as author. Imprint at bottom: Königsberg, gedruckt bey Martin Eberhard Dorn, 1746.
Immanuel Kant, Gedanken von der wahren Schätzung der lebendigen Kräfte, 1749 (title page shown from a later printing dated 1746).

About this source

What it is

This is Immanuel Kant's first published book, written in German as Gedanken von der wahren Schätzung der lebendigen Kräfte. Though written around 1744–46, it was not published until 1749 due to financial delays. It has a preface and three chapters.

Why it matters

In this early work, young Kant entered the scientific and philosophical debate between Descartes, Leibniz, and their followers over how to measure force in nature. He criticized Leibniz's followers while staying close to Leibniz's own ideas, showing his early effort to mediate between rival schools of thought.

Look closer

  • What does it mean that this was Kant's first published work — what might that tell us about his early interests?
  • Why might a young philosopher want to intervene in a scientific debate between famous thinkers?
  • What does the title page's printer and date tell you about how books were made in the 1740s?

This book is part of the curated material that grounds the AI version of Immanuel Kant 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 1781 first edition of Kant's Critique of Pure Reason. Blackletter title reads Critik der reinen Vernunft, von Immanuel Kant, Professor in Königsberg. Below: Riga, verlegts Johann Friedrich Hartknoch, 1781, with a floral wreath ornament.Book

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Critique of Pure Reason

Immanuel Kant · 1781 (revised 1787)

Printed page in German blackletter type headed 'Beantwortung der Frage: Was ist Aufklärung?' with the opening lines of Kant's essay, beginning 'Aufklärung ist der Ausgang des Menschen aus seiner selbst verschuldeten Unmündigkeit.' Page footer reads '2ter Band'.Book

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Answering the Question: What Is Enlightenment?

Immanuel Kant · 1784

Title page of Kant's Grundlegung zur Metaphysik der Sitten, printed in black Fraktur blackletter: 'Grundlegung zur Metaphysik der Sitten, von Immanuel Kant', with a decorative rococo ornament, a rule, and 'Riga, bey Johann Friedrich Hartknoch 1785' on a cream page.Book

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Groundwork of the Metaphysic of Morals

Immanuel Kant · 1785

Title page of Kant's 'Zum ewigen Frieden' printed in black Fraktur type. Text reads 'Zum ewigen Frieden. Ein philosophischer Entwurf von Immanuel Kant', with publication line 'Königsberg, bey Friedrich Nicolovius, 1795' at the bottom.Book

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Perpetual Peace: A Philosophical Sketch

Immanuel Kant · 1795

Title page of the 1788 German edition of Kant's Critique of Practical Reason: 'Critik der practischen Vernunft von Immanuel Kant', with a floral wreath ornament, 'Riga, bey Johann Friedrich Hartknoch 1788', and a purple library stamp at bottom right.Book

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Critique of Practical Reason

Immanuel Kant · 1788 (completed 1787)

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