The Discourse on Metaphysics has long been considered one of Leibniz’s most important works, as the first comprehensive presentation of his central philosophical positions, specifically on God, the soul, individual substance, natural laws, perception, expression, truth, knowledge, ideas, free will, sin, grace, and more. Composed in 1686, but unpublished in his lifetime, it first appeared in 1846 and subsequently in twelve editions of the original French, as well as in thirty-seven translations in as many as fifteen languages, including nine in English. Two French commentaries appeared in 1957 and 1959 and an English translation-commentary appeared in 2020. The work remains an important focus of scholarly attention and is frequently taught in university courses on seventeenth-century (Early Modern) philosophy.

This is a translation of and commentary on Leibniz’s Discours de Métaphysique, based on the edition published in 1999 by the Berlin-Brandenburgischen Akademie der Wissenschaften (Berlin-Brandenburg Academy of Sciences). It makes extensive use of the Academy’s ‘variant apparatus’, which records every deletion, addition, and revision Leibniz made to his first and second drafts. I translate most of the variants, placing them below the main text of the Discourse, and present the main text as a final version, which is virtually identical to Leibniz’s second draft (the ‘fair copy’). The translation thus provides the reader with the means of tracing the development of Leibniz’s thought as he wrote and revised the work. I have also closely examined the digital copies of the manuscripts, consulted other English translations and French editions, and added clarificatory notes. I aim to offer a scholarly translation that is at the same time student friendly. In addition to the commentary, this edition includes a chronicle of Leibniz’s work and activity during the year prior to having composed the Discourse until one year afterward, and includes several letters during that period, previously untranslated in English.

Although the content of the Discourse is comprehensive in scope, it consists of a series of sketches of positions that often lack argument and sufficient detail. Thus, the work can be quite challenging not only for students, but for teachers as well.