Leibniz on Freedom & Contingency

I discuss Leibniz’s position on freedom and contingency. It is important for Leibniz that his view allow for the ability to do otherwise, or leeway in action, that we take to be exemplified in saying of some act that it was possible for it not to be done (or the event not to occur, etc.). Thus, though Liebniz accepts a seemingly unrestricted form of the PSR, he does not want to accept the kind of so-called “necessitarian” position of Spinoza. The question is whether Leibniz succeeds in doing so.

1 The Problem of Freedom

When philosophers talk about freedom of the will they mean to indicate a capacity of agents to choose a desired course of action from among a set of relevant alternatives (note that the relevant alternatives might be rather sparse, so that the choice is simply whether to act or refrain from acting). This kind of freedom has been thought by many to be essential for attributions of moral responsibility, and for the praise or blame that we parcel out to ourselves and others based on such attributions.1

So if we understand the will as a capacity to choose between a desired course of action from a set of relevant alternatives, we can distinguish between cases where the capacity is clearly constrained, and thus where the will is not free, from cases where it seems clearly unconstrained (though this notion itself needs further elucidation). Clear cases of the former include cases such as being brainwashed, or manipulated. In such cases the subject does not have proper control over her actions, and thus is not, in the relevant sense, expressing any agency in her behavior.

What counts as a case where one is uncontroversially “unconstrained” cases is perhaps trickier. There seems nothing more obvious concerning the existence of an unconstrained will than in which one spontaneously and unbidden from any external source, produces a volition (e.g. to raise one’s arm) and then acts accordingly (i.e. raises her arm). Now, there is a clear contrast, with regard to control, between this case and the mind-control or brainwashing case. But many have thought that there remains an issue regarding the relevant notion of freedom, for we can ask whether the volitions of the agent were themselves determined in a sense which is incompatible with the characterization of the subject’s will as free.

The sense of “determination” which people are concerned with is often termed causal determination (or “natural causal determinism”), and more specifically, of being determined by the laws of nature plus preceding events (or the state of the universe as a whole).2 More generally, we can think of “determinism” as meaning the necessitation of an act, property, or event to the exclusion of any alternative. Determination thus is a form of exclusion, which excludes according to a law. This notion is quite broad. We could say that a triangle is “determined” by its three sides to have three angles, and for the sum of its angles to be equal to two right angles, etc. Its three-sidedness is the “determining ground” of its three-angledness. The notion of “exclusion” here is that of setting one of two opposing predicates as the predicate of a being or substance. Here “opposing” typically means logically opposing, as in, e.g., the predicates <hot> and <not-hot>. So the concept <triangle> contains the predicate <three-sided>, and the presence of this predicate both excludes <not-three-sided> and entails <three-angled>. Thus the complete concept of any individual contains predicates that are the determining grounds of its excluding any other way of being.3

The issue of determination, and of the existence of such determining grounds, immediately raises issues for freedom of the will. There are typically thought to be two responses to determinism, either free will is compatible with determinism (i.e. with there being a determining ground of the will), or it is incompatible. In what follows, we’ll look at whether Leibniz was a compatibilist or incompatibilist, and his reasons for being so.

2 Leibniz on Free Will

Understanding Leibniz’s views on freedom and determinism requires revisiting his notion of a substance, and the complete individual concepts which specify substances.

2.1 Complete Individual Concepts

In §8 of his Discourse on Metaphysics Leibniz says the following:

since activity and passivity pertain distinctively to individual substances (actiones sum suppositorum), it will be necessary to explain what such a substance is. It is of course true that when a number of predicates are attributed to a single subject while this subject is not attributed to any other, it is called an individual substance. But this is not enough, and such a definition is merely nominal. We must consider, then, what it means to be truly attributed to a certain subject. Now it is certain that every true predication has some basis in the nature of things, and when a proposition is not an identity, that is to say, when the predicate is not expressly contained in the subject, it must be included in it virtually. This is what the philosophers call in-esse, when they say that the predicate is in the subject. So the subject term must always include the predicate term in such a way that anyone who understands perfectly the concept of the subject will also know that the predicate pertains to it. This being premised, we can say it is the nature of an individual substance or complete being to have a concept so complete that it is sufficient to make us understand and deduce from it all the predicates of the subject to which the concept is attributed. An accident, on the other hand, is a being whose concept does not include everything that can be attributed to the subject to which the concept is attributed. Thus the quality of king which belonged to Alexander the Great, if we abstract it from its subject, is not determined enough to define an individual, for it does not include the other qualities of the same subject or everything which the concept of this prince includes. God, on the contrary, in seeing the individual notion or ’haecceity’ of Alexander, sees in it at the same time the basis and the reason for all the predicates which can truly be affirmed of him -for example, that he will conquer Darius and Porus- even knowing a priori (and not by experience) what we can know only through history - whether he died a natural death or by poison. Thus when we well consider the connection of things, it can be said that there are at all times in the soul of Alexander traces of all that has happened to him and marks of all that will happen to him and even traces of all that happens in the universe, though it belongs only to God to know them all (Leibniz 1969, 307–8).

So a complete concept (or ’notion’) is one which specifies the ’nature’ or essential features of a substance. From knowledge of the nature of a substance one can deduce all its other features, in just the same way that from the knowledge of the essence of a triangle one can deduce all of its other features. This also means that there cannot be two distinct substances with the same nature. Every substance has its own unique nature, and every complete concept specifies the nature of a unique (possible or actual) substance.

There is an obvious problem that arises for freedom of the will on the view thus described. If all the features of a substance may be derived from its complete concept, including everything that it has ever done, and everything that it will do, how could it be the case that human beings (who are substances after all) have the requisite freedom of will, since all of their acts of will/actions have a determining ground?

Leibniz states this problem very clearly at the beginning of §13 of the Discourse.

before we go further we must try to meet a great difficulty which may grow out of the foundations which we have laid above. We have said that the concept of an individual substance once and for all includes everything which can ever happen to it and that in considering that concept, one can see everything which can truly be predicated of it, just as we can see in the essence of the circle all the properties which can be deduced from it. But it seems that this will destroy the distinction between contingent and necessary truths, that it will leave no place for human liberty, and that an absolute fatalism will rule over all our actions as well as over the other events of the world. To this I reply that we must distinguish between what is certain and what is necessary (Leibniz 1969, 310).

To understand this distinction between what is ’certain’ and what is ’necessary’ we need to look a little more closely at Leibniz’s theory of modality.

For Leibniz, a world is just a set of individual substances whose natures are such that they could all exist together (we can say that their natures are ’compossible’ just in case their mutual coexistence does not result in a logical contradiction), plus whatever natural laws are compatible with those substances being as they are. Now, according to Leibniz, the creator of all these substances is God, and God always acts for the best (DM §5). This is in line with Leibniz’s endorsement of the Principle of Sufficient Reason (PSR). God always acts for a reason (to do otherwise would violate the PSR) and God’s ultimate reason for acting can always be understood in terms of optimality, or bringing about the best. So the PSR coupled with this Optimality Principle (OP) entails that God actualizes the existence of a plenitude of substances whose natures are compossible, so as to bring about the creation of the best of all possible worlds.

The notion of a possible world is the notion of a set of complete individual concepts whose essences are compossible, and which God could have made actual (i.e. God could have created the substances whose predicates are all specified by the complete individual concepts). So the actual world is the set of compossible complete concepts actualized as substances (or natures thereof) that God chose to actualize according to PSR and OP, while the possible worlds are all those would-be substances defined by complete concepts which `exist’ only in the divine intellect.

So Leibniz can appeal to these `unactualized’ or merely possible substances whose concepts exist in the divine intellect in order to explain our modal talk of possiblia. For example, if I say that it was possible for me to finish the race had I not broken my ankle, then Leibniz understands this as meaning that there is a world of compossible complete individual concepts of substances in which a being very much like me (though not exactly like me—call this my `counterpart’) did finish the race.

2.2 Freedom of Choice

If Leibniz now has a means for accounting for the difference between actual and the possible, what about the necessary? Leibniz considers the truly or absolutely necessary to be anything whose contrary is or entails a logical contradiction.4 It is here that Leibniz hopes to find some wiggle room for characterizing his particular flavor of compatibilism.

I say that there are two kinds of connection or sequence. One is absolutely necessary, for its contrary implies a contradiction, and this deductive connection occurs in eternal truths like those of geometry. The other is necessary only ex hypothesi, and by accident, so to speak, and this connection is contingent in itself when its contrary implies no contradiction. A connection of this kind is not based on pure ideas and on the simple understanding of God but also on his free decrees and on the sequence of events in the universe. Let us take an example. Since Julius Caesar is to become perpetual dictator and master of the republic and will destroy the liberty of the Romans, this action is contained in his concept, for we have assumed that it is the nature of such a perfect concept of a subject to include everything, so that the predicate is included in it - ut possit inesse subjecto. One could say that it is not by virtue of this concept or idea that he must commit this act, since the concept fits him only because God knows everything (Leibniz 1969, 310).

Here Leibniz distinguishes between something’s being (absolutely) necessary and something’s merely following with (hypothetical) necessity, given an antecedent condition. Leibniz then argues that while it is true that a person’s volitions, and ultimately their actions, follow from their nature as substances, this does not mean that those volitions or actions must absolutely necessarily happen, but only hypothetically necessarily happen. Leibniz then contends that hypothetical necessities are compatible with freedom of the will.

I say that whatever happens in conformity to these divine anticipations is assured but not necessary and that if anyone were to do the contrary, he would not do anything impossible in itself, though it would be impossible ex hypothesi for it to happen. For if some man were able to carry out the complete demonstration by virtue of which he could prove this connection between the subject, who is Caesar, and the predicate, which is his successful undertaking, he would actually show that the future dictatorship of Caesar is based in his concept or nature and that there is a reason in that concept why he has resolved to cross the Rubicon rather than stop there, and why he has won rather than lost the day at Pharsalus, and why it was reasonable and consequently assured that this should happen. But this man could not show that these events are necessary in themselves or that their contrary implies a contradiction. In the same way it is reasonable and assured that God will always do what is best, even though what is less perfect implies no contradiction. For it will be found that this demonstration of the predicate of Caesar is not as absolute as that of numbers or of geometry but that it supposes the sequence of things which God has freely chosen and which is founded on the first free decree of God, which leads him always to do what is most perfect, and on the decree which God has made about human nature (following the primary one), which is that man shall always do, though freely, that which appears to him to be best. But every truth which is based on this kind of a decree is contingent, even though it is certain, for these decrees do not change the possibility of things. And as I have already said, though God assuredly always chooses the best, this does not prevent something less perfect from being and remaining possible in itself, even though it will never happen, for it is not its impossibility but its imperfection which causes God to reject it. Now nothing is necessary whose opposite is possible (Leibniz 1969, 311).

So, given God’s creation of this actual world, it is certain that Caesar would cross the Rubicon, and Judas would betray Jesus, and that you would eat what you did for breakfast this morning. But none of these certainties (or, we might say, conditional or hypothetical necessities) is incompatible with the freedom of will that Caesar, Judas, or you yourself exercise, since there is no absolute necessity to these events. There are other possible worlds (in the sense explained above) in which these events do not occur.

On this view, every action has a determining ground, but every action is not thereby absolutely necessary because the series of determining grounds is not itself logically necessary, and thus in that sense could have been different (i.e. there is no contradiction in positing a different series).

Here one might object that freedom is incompatible with an action’s (or act of will) having any determining ground whatsoever. Free actions, one might contend, must be absolutely undetermined. Leibniz rejects this position,

If complete indifference is required for freedom, then there is scarcely ever a free act (Leibniz 1989, 22–23).

Why might Leibniz reject the position that freedom of will/action requires a lack of determination? Because such a free act would be in violation of the PSR, for it would entail that in acting as one does, one lacks a sufficient reason for doing so. Thus one’s acting as one does would be arbitrary or brute, and Leibniz rejects this possibility. Hence,

that a reason that always forces a free mind to choose one thing over another (whether that reason derives from the perfection of a thing, as it does in God, or from our imperfection) does not eliminate our freedom (Leibniz 1989, 20).

Whether this is a plausible position is something we’ll discuss, and will come up in a particularly sharp way in Kant’s work.5


Adams, Robert Merrihew. 1994. Leibniz: Determinist, Theist, Idealist. Oxford: Oxford University Press.
Bennett, Jonathan. 2001. Learning from Six Philosophers: Descartes, Spinoza, Leibniz, Locke, Berkeley, Hume. Oxford: Clarendon Press.
Carriero, John. 1991. “Spinoza’s Views on Necessity in Historical Perspective.” Philosophical Topics 19, No. 1, Modern Philosophy (Spring 1991): 47–96. doi:10.2307/43154090.
Carriero, John, Massimo Mugnai, and Daniel Garber. 1996. “Leibniz: Determinist, Theist, Idealist.” The Leibniz Review 6: 61–106. https://www.pdcnet.org/leibniz/content/leibniz_1996_0006_0000_0061_0106.
Jorati, Julia. 2017. Leibniz on Causation and Agency. Cambridge: Cambridge University Press. https://www.amazon.com/Leibniz-Causation-Agency-Julia-Jorati/dp/1107192676.
Leibniz, Gottfried Wilhelm Freiherr. 1969. “Discourse on Metaphysics.” In Philosophical Papers and Letters: A Selection, edited by Leroy E Loemker, 303–30. Dordrecht: Kluwer Academic Publishers.
———. 1989. Philosophical Essays. Hackett Publishing.
McKenna, Michael, and Derk Pereboom. 2016. Free Will: A Contemporary Introduction. New York: Routledge, Taylor & Francis Group.
Riley, Patrick. 1996. Leibniz’ Universal Jurisprudence: Justice as the Charity of the Wise. Cambridge, MA: Harvard University Press.
Stang, Nicholas F. 2019. “A Guide to Ground in Kant’s Lectures on Metaphysics.” In Kant’s Lectures on Metaphysics: A Critical Guide, edited by Courtney D. Fugate, 74–101. Cambridge: Cambridge University Press. https://philpapers.org/archive/STAAGT-3.pdf.
Van Inwagen, Peter. 1983. An Essay on Free Will. Oxford: Clarendon Press.

  1. For an overview of issues related to free will see (McKenna and Pereboom 2016). ↩︎

  2. For a classic recent argument against the compatibility of freedom with determinism in this sense see (Van Inwagen 1983). ↩︎

  3. For related discussion of Kant’s reception of the German rationalist tradition see (Stang 2019). ↩︎

  4. Contrary propositions are propositions which cannot both be true, though they might both be false. For example, ’The wall is (completely) blue’ and ’The wall is (completely) red’ are contraries. They cannot both be true, but they might both be false when, e.g., the wall is yellow. In contrast, contradictory statements are statements, one of which must be true. For example, ’the wall is red’ and ’the wall is not red’ are contradictory statements. A contradiction is a statement that is always false. ↩︎

  5. For a defense of Leibniz’s view of freedom and contingency see (Jorati 2017, chap. 5). For criticism (either of the overall theory with respect to freedom, or the particulars of Leibniz’s “infinite analysis” theory of contingency) see (Carriero 1991, 83; chaps Adams 1994, 1–2; Carriero, Mugnai, and Garber 1996, 63 f; Riley 1996, 85–88; Bennett 2001, chap. 17). ↩︎