A New Three Volume Edition of Leibniz’s Philosophical Papers (1677–1686)

For a philosopher whose ideas have rippled across logic, metaphysics, mathematics, and beyond, Gottfried Wilhelm Leibniz remains surprisingly under-translated. Descartes has his Cambridge edition; Spinoza has his Hackett and Princeton volumes; Kant has the Cambridge series. Leibniz, by contrast, has long been served by overlapping “best of” anthologies, many now outdated and based on unreliable transcriptions.

That gap is finally beginning to close. A new three-volume edition of Leibniz’s Philosophical Papers (1677–1686), published on April 30 by Oxford University Press, offers the most comprehensive English-language presentation to date of Leibniz’s writings. Drawing directly from manuscripts in Latin, French, and German, it makes available 2000 pages of material, much of it never before appearing in English, and some never previously published in any language.

But the significance of this edition lies not only in its scope but in the period of Leibniz’s development that it covers.

Leibniz arrived in Hanover in late 1676, after spending four years in Paris immersed in mathematics. He had no stable metaphysics to his name. What he had instead was an extraordinarily fertile and restless mind, bursting with ideas for projects that would occupy him for the rest of his life. Among the many projects he worked on at this time were:

• a new inventive logic or “art of discovery” designed to generate new truths both within philosophy and beyond
• a universal language with a philosophical grammar structured to reflect human reasoning
• a symbolic script (the characteristic) capable of facilitating discoveries across all fields of knowledge 
• an encyclopaedia that would reorganize existing knowledge to yield new insights 
• a rational physics grounded not in experiments but in an a priori investigation of intelligible and sensible qualities
• reorganizing and rationally grounding the body of law 
• resolving religious divisions 

Nor were these isolated pursuits, since all were intended to contribute to public benefit and the improvement of human life.

In pursuing these projects, between 1677 and 1686 Leibniz worked out the foundations of his philosophy. Across hundreds of essays, drafts, and fragments—many unpublished in his lifetime—he explored ideas that would later define his mature thought. These writings show not the polished author of the Monadology, but a philosopher in the midst of discovery. This edition brings that process into view.

What emerges from these writings is not a finished system, but a set of ideas that would become Leibniz’s signature doctrines. For example:

1. Incompossibility

Breaking with Spinoza, Leibniz argued that not all possible things can exist together in the same world because some are incompossible, or not jointly possible. Because of these incompatibilities, God must choose among alternative sets of possible things, being “morally necessitated” to choose the best set, but not logically or metaphysically compelled. This distinction, central to Leibniz’s later theodicy, preserves divine freedom.

2. The Doctrine of Striving Possibles

Leibniz reconceives possibility not as mere absence of contradiction, but as something with positive ontological status, namely a “disposition to exist.” Possible things are said to incline toward existence in proportion to their degrees of perfection, which determine their appeal to God, who selects the most perfect set of compossible possibles.

3. The Complete Concept Theory

In the late 1670s, Leibniz develops the idea that an individual substance has a complete concept containing all of its predicates, past, present, and future. This doctrine fuels later debates with Antoine Arnauld about freedom, necessity, and divine foreknowledge.

4. Contingency

If every predicate is contained in the concept of an individual, how can there be genuine contingency? Leibniz responds first with the claim that “reasons incline without necessitating,” here adapting a well-known Renaissance proverb about the stars. He later develops this into a sharp distinction between necessary and contingent truths: in the former, a finite analysis is sufficient to show that the predicate is contained in the subject, whereas in the latter, only an infinite analysis will do.

5. The Nature of Substance

Leibniz’s early writings in Hanover show him endorsing substantial forms, which he believed the Cartesians had wrongly discarded. Substances, he argues, are not mere extended things or thinking things, but composites of matter (the principle of passion) and form (the principle of action). These ideas culminate in the mature theory of monads, but their roots are here.

These doctrines are scattered across a wide range of texts from the period. The three volumes bring them together for the first time in a comprehensive and accessible form.

Between them, the volumes present 314 distinct writings from this period, grouped thematically:

• Universal Language, Characteristic, Logic, Encyclopaedia, and General Science: 124 writings
• Metaphysics, Natural Philosophy, Ethics, and Jurisprudence: 138 writings
• Religion and Theology: 52 writings

In total, 203 of these texts appear in English for the first time, and seven have never been published in their original language. These include texts on teaching languages, definitions of logical and metaphysical terms, methods in the mechanical arts, jurisprudence, and religious controversy.

But the significance of the volumes lies not only in what they contain, but in how they have been constructed.

What most distinguishes this edition is that the translations are made directly from the original manuscripts rather than from earlier printed editions. This matters more than one might think, as even the best available transcriptions often contain errors, sometimes small, sometimes significant enough to obscure Leibniz’s meaning. Getting the palaeography right reveals details of Leibniz’s philosophy that would otherwise be obscured.

This commitment to manuscript fidelity also means that the edition avoids the “hybrid” texts that have crept into some earlier translations. The most notable case is Leibniz’s seminal essay “Discourse on Metaphysics,” where editors have often merged elements from multiple drafts. In this edition, each manuscript version is presented separately, allowing readers to see the development of Leibniz’s thought rather than a synthetic version he never produced.

In addition, some of the texts in the edition have been re-dated using fresh internal and external evidence. Overturning long-accepted dates is not a minor editorial exercise but a crucial one for understanding the evolution of ideas. Dating matters: move a text by three years and the philosophy moves with it. The edition also records Leibniz’s marginalia and thousands of his deletions, offering an unusually detailed view of his working methods, change of direction, and dead ends.

The result is a more faithful—and more philosophically illuminating—picture of Leibniz at work, enabling us to see not just what he thought, but when he thought it and the labor behind it.

For scholars, this edition makes available a vast body of material that has long been difficult to access, misdated, mistranscribed, or simply unknown. For students, it offers the opportunity to encounter Leibniz not as a canonical figure distilled into a handful of polished texts, but as a working philosopher. Here we see the metaphysician before the Monadology, the epistemologist before the New Essays, the theologian before the Theodicy. We see a thinker developing, revising, and testing out ideas that would later become central to his mature system while quietly abandoning others. In short, we see Leibniz thinking. For a philosopher as influential and as misunderstood as Leibniz, that alone makes this edition an important new resource.