Leibniz ranks as an outstanding polymath even among the intellectual giants of the seventeenth century. He was a mathematician, scientist and philosopher; a lawyer, diplomat, engineer, inventor and historian. He saw his investigations in these several fields as constituting a complex but coherent whole, because all his work was grounded on his comprehensive and unifying metaphysical system.

Leibniz’s fundamental tenet was that reality ultimately consists of an infinite number of non-material substances. These entities he calls monads: ‘simple substances without parts and without windows through which anything could come in or go out’. God, he maintains, is an infinitely perfect being who, from an infinite number of possible worlds, creates the best possible world within which everything unfolds in accordance with a pattern he has pre-established and which follows from his first decrees. Leibniz believed that philosophy was of great practical importance and that it could not only resolve theological and political issues but could also provide a coherent basis for scientific and mathematical developments. His vision was of a great synthesis of knowledge, a universal encyclopaedia that would be accessible through catalogues, abstracts and indices to the international community of scholars who, when confronted with large political and social problems, would be able to sit down together and calculate correct solutions. He saw himself as a citizen of the world rather than of the small state of Hanover which he served for much of his life. This breadth of outlook is apparent in the numerous brilliant and wide-ranging projects that constitute his prodigious output.

Leibniz was born in Leipzig a few years before the Thirty Years War ended. His father, a professor of philosophy at Leipzig University, taught him to read at an early age. Thereafter his intellectual abilities developed rapidly. He was enrolled in the university at the age of 14, graduated two years later and proceeded to work for and obtain a doctorate in law which was awarded him in 1666 at the University of Altdorf. He refused a professorship there but worked for a short while as secretary to a Nuremberg society interested in alchemy, a topic in which he retained an interest for the whole of his life. He then entered the service of the Archbishop of Mainz who sent him on a mission to Paris.

There he met, among others, the philosopher Malebranche, Arnauld, the theologian and philosopher, and Huygens, the Dutch physicist. He extended his knowledge of mathematics and invented a calculating machine superior to one made by Pascal.
In 1673, Leibniz visited London and was elected a member of the Royal Society. In that same year the Archbishop of Mainz died and Leibniz found himself without a job.
Somewhat reluctantly, because it did not appeal to him at all, he eventually accepted the post of Librarian to the Duke of Brunswick at Hanover. On the way to taking up the work he went to Amsterdam where he visited Spinoza with whom he enjoyed four days of lively discussion. Sadly, this was his last opportunity to engage in stimulating philosophical exchanges. Thereafter, he lived and worked in Hanover, save for the few journeys required by his work, and he had contact with other scholars only through letters and the exchange of papers. His main task as Librarian was to write a history of the House of Brunswick, but while compiling this he worked in many other fields as well.

Leibniz became involved in a most unhappy controversy about the discovery of the infinitesimal calculus. It seems that both he and Newton, as well as other European mathematicians, were working on the calculus at the same time and a dispute arose over who in fact was to be deemed its author or discoverer. Newton was able to stand aside from the dispute because many of his friends vigorously made a case for him. But Leibniz had fewer defenders to rally to his aid and had to resort to pleading his own case.
He did this by writing anonymously in his own defence, a wretched procedure to have to engage in, and particularly so as his authorship of the defence soon became apparent.

Whatever the precise truth of the controversy may be, time has shown that Leibniz’s notation, which is still used, is regarded as more satisfactory than Newton’s. Leibniz’s biographers have pointed out that he suffered further disappointment in that his highly original work in logic was not acknowledged by his contemporaries. His achievements in logic are now clearly recognised, but his copious writings on the subject lay disregarded in the Royal Library in Hanover until early in the twentieth century. His death in 1716 was more or less ignored by the Hanoverian court, the Royal Society in London, and the Academy of Berlin. A number of factors contributed to this unpopularity, among them his tendency to be snobbish and arrogant; but most of the hostility seems to have been provoked by Leibniz’s opposition to nationalism and his vision of a single universal society. In this, as in so many of his ideas, he was much in advance of his time.

Leibniz’s best-known works are the Discourse on Metaphysics (1686), the New Essays Concerning the Human Understanding (1704), the Theodicy (1710) and the Monadology (1714). Only the Theodicy was published in his lifetime. Equally famous is the series of letters he exchanged with the French anti-Jesuit theologian, Antoine Arnaud, concerning freedom and the concept of an individual, and with Samuel Clarke, a leading member of Newton’s circle, concerning the Newtonian universe. But no mere listing of his writings, even if it were comprehensive, can indicate the scope of his interests, abilities, inventiveness, sheer intellectual power, and prodigality. The task of compiling a complete edition of his works did not begin until 1923 and has continued into the twenty-first century.

Whereas Descartes maintained that reality consists fundamentally of two substances, and Spinoza maintained that there is only one, Leibniz argued a case for infinitely many substances which he called monads. Leibnizian monads are the simplest units of existence and each monad is a different simple substance which is unextended and without parts. Thus, ultimate reality, for Leibniz, does not consist of anything physical.

We have to think of the monads as energy rather than matter and as differing from each other in virtue of possessing differing degrees of consciousness. A human being is a colony of monads in which the dominant monad is a spirit monad that unifies the colony in virtue of being conscious, to a certain extent, of its members. The individual monads can only be created or annihilated ‘all at once’ by God and each monad carries within itself, from its creation, the potentiality of all it will ever be. Each monad unfolds its being in a way which is harmonious with the unfolding of every other monad, but without ever affecting or being affected by any other monad. In creating the universe, God is able to conceive of an infinite number of possible worlds and he creates the best of all possible worlds. He does not create a perfect world, for that is logically impossible. To create a perfect world God would have t reproduce himself exactly. But since God is nonextensive spirit, a reproduction of his qualities would be indiscernible and so nonexistent.

Thus the best of all possible worlds is the one containing as much existence as possible compatible with the greatest degree of perfection. God knows and foresees every detail of the unfolding of every monad as well as every relationship and complex of relationships through which every monad will pass as it unfolds itself.

In para. 59 of the Monadology, Leibniz says, ‘Now this connection or adaptation of all created things with each, and of each with all the rest, means that each simple substance has relations which express all the others, and that consequently it is a perpetual living mirror of the universe.’ Because each monad mirrors the universe from a different point of view ‘it is,’ he says, ‘as if there were as many different universes, which are, however, but different perspectives of a single universe in accordance with the different points of view of each monad’. Each monad is in a sense representative of the whole, although it does not reflect the whole, for only a divinity could do that. Leibniz says: ‘It is not in the object, but in the modification of the knowledge of the object, that monads are limited.’ The apparent interaction of things in everyday experience is in fact the consequence of God’s ordination. It is the working out of a pre-established harmony known in its entirety only to God.

Leibniz bases his philosophy on some very general principles. The first is that reality consists of substances and their attributes. Logically, or grammatically, this is to say that he thought in terms of subjects to which predicates are ascribed. He also accepted certain fundamental principles of thought: the principle of contradiction, which holds that any statement containing a contradiction is false and its opposite is true; and the principle of sufficient reason, which holds that there is a sufficient reason for everything being as it is.

A particular type of truth derives from each of these two principles. Truths of reason, which are necessary truths the opposites of which are impossible, derive from the principle of contradiction. Truths of fact, which are contingent truths the opposites of which are possible, derive from the principle of sufficient reason.

Necessary truths are shown to be so by analysis. The necessary truth ‘A bachelor is an unmarried male’ is shown to be necessary once one considers the definitions of the terms ‘bachelor’ and ‘unmarried male’. For truths of fact there are sufficient reasons; but if one enquires into the reasons for a particular state of affairs, say for the fact that a particular table is occupying a particular position, then it is possible to go on and on adducing more and more ‘reasons’. In Leibniz’s system, only God can know all the reasons for a contingent truth’s being what it is. God is the ultimate and sufficient reason for every contingent truth and his intellect can grasp everything pertaining to a truth, so that, for him, every contingent truth is as analytically true as a truth of reason. This is simply another aspect of the doctrine that a monad, when created, contains within it all that it will ever be. The logical expression of the doctrine is that in any true proposition the concept of the predicate is contained in the concept of the subject; the complete concept of a monad and, by extension, of any aggregate of monads, contains everything that can truly be said of it.

An important and perhaps dismaying consequence of Leibniz’s doctrines is that many of our ordinary beliefs about our ability to make choices and our capacity to influence or be influenced by others seem to be untenable. Just this objection was made by the theologian, Antoine Arnauld, and was met by Leibniz in letters exchanged between the two. In 1686 Leibniz sent a summary of his Discourse on Metaphysics to Arnauld, who, upon reading it, declared that it contained many startling things, and wrote to his patron, Landgraf Ernst Von Hessen-Rheinfels, in the following terms:
I find in these meditations so many things which frighten me, and which, unless I am much mistaken, all mankind will find so shocking, that I do not see that any purpose would be served by a piece of writing which will manifestly be rejected by the whole world.

Arnauld was deeply shocked by Leibniz’s account because, he said, it seemed to impose restrictions not only on the liberty of individuals but on that of God as well; for if the concept of an individual involves everything that will ever happen to him, the liberty of God is restricted in that having once decreed the existence of an individual, then that existence will follow an inevitable course which God would be unable to alter. Moreover, the liberty of any person is quite non-existent, since the events of every individual’s life are pre-chosen. Thus, if God, in allowing Adam to exist, knows all that Adam will do, we can only conclude that Adam is determined and has no choices. Likewise God, having brought about the existence of Adam as a colony of monads containing the potentiality of all that Adam will ever be, can only allow Adam to be just that and nothing else.

To this, Leibniz replies by invoking the distinction between truths of reason and truths of fact, and by emphasising some points he has already made in paragraphs 8 to 13 of the Discourse. Adam, he says, does not do all he does out of logical necessity: upon waking in the morning it is logically possible for Adam that he may rise and walk or may lie longer in the Garden, enjoying its delights. There will be sufficient reasons for what he in fact does, and these reasons will be known to God. But although God has decreed and knows what Adam will do, so that it is certain that Adam will do what he does, it is never logically necessary that Adam does what he does, and it is always logically possible that he might do otherwise. To the objection that his theory restricts God’s freedom, Leibniz answers that God’s freedom is not exemplified in arbitrary acts. The greatest freedom is to act in accordance with what is good and this is what God freely chooses to do. He has freely chosen to create the best of all possible worlds, and the whole orderly system of the world as we know it stems from God’s first decree.

Arnauld is not satisfied with Leibniz’s replies. His own view is that the concept of an individual such as himself includes ‘only what is of such a nature that I would no longer be myself if it were not in me’; it does not have to include ‘everything that will ever happen to me’. He believes that he is defined by a range of features essential to his being himself but that ‘everything which is of such a nature that it might either happen to me or not happen to me without my ceasing to be myself, should not be considered as involved in my individual concept’. Thus, according to Arnauld, if an individual is defined as a type of human being, for example as male, celibate, a theologian, then his human freedom would consist in his living out the details of these roles in his own particular way. But such a view is inadmissible in Leibniz’s metaphysics, the basis of which is the concept of the monad as self-contained, complete, and chosen by God to be and do everything that it will ever be and do.

To some, Leibniz’s account of the way things really are may sound strange, even fantastic. For Leibniz himself, the postulation of an infinite number of extensionless and self-contained substances, created by a God possessing infinite perfection and cognisant of all possibilities and actualities, was simply the conception of reality that resulted from rational reflection concerning the way things ultimately must be. Moreover, he believed that rationally-conceived principles must provide the grounds of the empirical sciences; in short, that the logico-metaphysical structure arrived at by the process of reason is a fully adequate foundation for the world of appearances: for the phenomena of matter, bodies, space, time, motion, and all the interactions of human beings.



Leibniz Chronology
Chronology is a collection of bladders of wind. All who thought to pass over it as solid ground have been immersed. -Voltaire-


Note: Dates are given according to the Gregorian calendar.

1646 1 July: Born in Leipzig, the son of Friedrich Leibniz (1597–1652), professor of moral philosophy at the University of Leipzig.

1648 End of the Thirty Years War.

1650 Death of Rene Descartes.

1651 Publication of Thomas Hobbes’s Leviathan.

1652 Leibniz’s father dies, leaving him to be brought up by his mother.

1653 Enters the Nicolai School in Leipzig.

1661 Enters the University of Leipzig. His teachers include Jakob Thomasius and Johann Scherzer.

1663 Defends and publishes his bachelor’s thesis, Metaphysical Disputation on the Principle of Individuation. Attends some lectures by Erhard Weigel at the University of Jena.

1664 Defends and publishes his master’s thesis on philosophy of law, entitled Specimen quaestionum philosopharum ex jure collectarum.
His mother dies.

1665 Studies law and receives his bachelor’s degree.

1666 Publishes Dissertation on the Combinatorial Art. Writes his doctoral thesis in law, On Difficult Cases in Law, but the degree is refused by Leipzig. Moves to the University of Altdorf.

1667 Receives doctorate in law from Altdorf. Takes a position as secretary to an alchemical society in Nuremburg. Moves to Frankfurt and publishes his New Method for Learning and Teaching Jurisprudence.

1668 Moves to Mainz, where he is appointed to the High Court of Appeal by the elector. Catalogs the library of Baron Johann Christian von Boineburg. Writes an anonymous tract supporting the elector’s candidate to be king of Poland.

1669 Engages in ecclesiastical diplomacy and in writing about theology and philosophy of religion, including the drafts known as The Catholic Demonstrations. Publishes anonymously his Confession of Nature against the Atheists.

1670 Produces for Boineburg an edition of Nizolius’s Anti-Barbarus, with a preface. Works on physics and studies Hobbes. Writes his only letter to Athanasius Kircher, whose works he had read and admired.

1671 Publishes anonymously the New Physical Hypothesis.

1672 Goes to Paris on a secret diplomatic mission to present a peace plan for Europe. Meets Antoine Arnauld and Christiaan Huygens. Boineburg dies. His sister, Anna Catherina, dies.

1673 Travels to London in hope of setting up a peace conference. Meets Henry Oldenburg, secretary of the Royal Society, and Robert Boyle. Demonstrates a model of his calculating machine.
Elected a fellow of the Royal Society in London. The elector
of Mainz dies. Leibniz returns to Paris and begins intensive study of higher mathematics. Writes Confession of a Philosopher.

1674 Working on mathematical problems and on completing his calculating machine.

1675 Makes a breakthrough with the infinitesimal calculus. Meets Nicolas Malebranche and Ehrenfried Walther von Tschirnhaus.
Begins a 20-year correspondence with French cleric Simon Foucher. Begins the writings that form the De summa rerum.

1676 Decides to accept employment with Johann Friedrich, Duke of Hanover. First (indirect) exchange of letters with Isaac Newton.
Travels via London to Holland where he visits the microscopists Jan Swammerdam and Antoni van Leeuwenhoek in Amsterdam and Delft, and Benedict de Spinoza at The Hague.
December: Arrives in Hanover.

1677 Publishes the diplomatic work De jure suprematis. Second exchange of letters with Newton. Spinoza dies.

1678 Receives a copy of Spinoza’s Ethics. Continues work on the universal characteristic.

1679 Begins his involvement in the Harz mine-draining scheme. Begins a 23-year correspondence with Jacques Benigne Bossuet, later to become bishop of Mieux, and a long correspondence with Ernst von Hessen Rheinfels. Johann Friedrich dies and his dukedom passes to Ernst August, whose wife Sophie and later their daughter Sophie-Charlotte become Leibniz’s trusted friends and correspondents. Hobbes dies.

1682 Publishes the first of about 50 articles in the Acta Eruditorum.

1684 Publishes New Method for Maxima and Minima and Meditations
on Knowledge, Truth, and Ideas.

1685 His involvement in the Harz mine projects ends. Researching the history of the House of Brunswick-Luneburg becomes his principal official duty. Birth of George Berkeley.

1686 Completes the first draft of the Discourse on Metaphysics. Correspondence with Arnauld begins. Publishes Brief Demonstration of a Notable Error of Descartes.

1687 Leaves Hanover on a journey that takes him, over the next three years, to southern Germany, Austria, and Italy, officially researching the history of the House of Brunswick. Begins a 10- year correspondence with professor of mathematics Jakob Bernoulli. Publication of Newton’s Principia.

1688 Meets the Kabbalah scholar Christian Knorr von Rosenroth in Sulzbach. Conduct numerous trips and meetings in furtherance of his interests in geology, mineralogy, and natural history.

1689 Publishes Schediasma de resistentia and Tentamen de motuum coelestium causis.

1690 Returns to Hanover. Corresponds with Paul Pellison-Fontanier on issues of church reunion. First uses the term monad, in a letter to Michel Angelo Fardella. Publication of John Locke’s Essay Concerning Human Understanding.

1691 Takes up the directorship of Wolfenbuttel Library. Finishes Dynamics.

1692 Begins correspondence with Guillaume de’Hopital on mathematics.

1693 Exchanges letters directly with Newton. Begins correspondence on mathematics with Johann Bernoulli that lasts until Leibniz’s death. Publishes Code of the Law of the Peoples (Codex juris gentium diplomaticus).

1695 Publishes part 1 of Specimen of Dynamics

1696 Carries on conversations with Christian kabbalist Francis Mercury van Helmont, whose Thoughts on Genesis Leibniz is secretly involved with. Pierre Bayle publishes his remarks on the New System in his Dictionnaire historique et critique. Leibniz proposes marriage, but then rescinds the offer.

1697 Writes On the Radical Origination of Things. Corresponds with Joachim Bouvet on Chinese philosophy and binary notation.
Priority dispute concerning the discovery of the calculus begins.

1698 Ernst August dies and is succeeded by Georg Ludwig, with whom Leibniz has a troubled relationship. Publishes On Nature Itself. Corresponds with Burkhard De Volder on dynamics and metaphysics.

1700 Founding of the Berlin Society of Sciences, with Leibniz as the first president. He is also elected a foreign member of the Royal Academy of Sciences in Paris.

1701 Joins in negotiations concerning Georg Ludwig’s accession to the English throne following the Act of Settlement. Begins correspondence on mathematics with Pierre Varignon.

1702 Debates with John Toland in the presence of Sophie-Charlotte in Berlin.

1704 New Essays Concerning Human Understanding is mostly complete. Begins a correspondence on mathematics with Jakob Hermann. Meets Princess Caroline of Ansbach. Locke dies.

1705 Makes first contact with mathematician Christian Wolff. Mourns the death of Sophie-Charlotte.
Publishes Thoughts on Vital Principles and Plastic Natures.

1706 Meets and subsequently corresponds with Bartolomaeus Des Bosses, a Jesuit philosopher, mathematician, and theologian.
Secretly composes, prints, and circulates a letter for Sir Rowland
Gwyne advancing the case of the Hanoverian succession; the letter is condemned by Parliament.

1710 Publishes Theodicy anonymously. Publication of Berkeley’s A Treatise Concerning the Principles of Human Knowledge.

1711 First of several audiences with Tsar Peter the Great, who commissions him to propose reforms of the law and the administration of justice in Russia. Birth of David Hume.

1712 Second edition of Theodicy is published with Leibniz’s name. Royal Society makes the pronouncement that Newton discovered the calculus first.

1713 Appointed an Imperial Privy Counsellor in Vienna and establishes plans for a Society of Sciences there.

1714 Composes the Principles of Nature and Grace, Founded on Reason and the Monadology (see image 3). Begins correspondence with Nicolas Remond, a French Platonist. Sophie dies.
Georg Ludwig ascends the English throne as George I. Leibniz returns to Hanover.
1715 Starts correspondence with Samuel Clarke, via Princess Caroline.
Malebranche dies.

1716 Writes the Discourse on the Natural Theology of the Chinese. Discusses with Daniel Jablonski proposals for reunifying the Anglican and Lutheran churches.

14 November: Leibniz dies, at age 70.

14 December: Funeral and burial at Neustadter church. All his papers are taken into care by the Electoral Library.

1717 Clarke publishes his correspondence with Leibniz.

1718 Principles of Nature and Grace, Founded on Reason is published in L’Europe savante. J. Feller publishes Leibniz’s 1696–1698 correspondence.

1720 Monadology is first published, in German translation, by Heinrich Koehler.

1721 First Latin translation of Monadology, by M. G. Hansch, is published in Acta Eruditorum Supplementa. Wolff publishes his Vernuenfftige Gedancken von Gott; his teachings are associated by many with Leibniz’s for about a hundred years hence.

1723 Church historian Joachim Lange attacks Wolff and Leibniz in his Kontroversschriften gegen die Wolffische Metaphysik. G. Bilfinger publishes a defense of Leibniz’s pre-established harmony in his De Harmonia animi et corporis humani.

1734 G. Kortholt publishes Leibniz’s correspondence over the next eight years.
C. Ludovici publishes a catalog of Leibniz’s known works. The Jesuit journal Mémoires de Trevoux reviews the Theodicy, but is undecided regarding its possible Spinozism.

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