Leibniz on Possibilia, Creation, and the Reality of Essences

1. Introduction

Leibniz famously holds that, in creating the world, God chooses between possible worlds, actualizing one of them — the most perfect one. Possible worlds are constituted by possible individual substances. Creation thus amounts to God’s choosing to actualize some of all of the possible individuals and presupposes “an infinite number of series of possible things” only some of which “attain existence” (A VI.iv, 1651/AG, 29).¹ This paper proposes to radically reconsider Leibniz’s conception of the nature of possible things (possibilia), as well as the very ground of possibility.

There is a close connection between Leibniz’s idea of possible things and his idea of finite individual essences.² That there is a genuinely possible thing, apt to be created, means that there is an individual essence endowed with a degree of reality or perfection. To ask about the nature of possible things is thus to ask about the nature of essences and their reality. Our main focus will be on what Leibniz understands by the reality of essences. We believe that this central element in Leibniz’s system has thus far not been correctly interpreted and that the main reason for this is that his readers have tended to see Leibniz’s concern with the reality of essences as primarily a concern about their ontological status, or the kind of being or existence they have. In contrast, we shall argue that the question concerning the ontological status of essences is importantly different from that of their reality, which pertains to the very ground of possibility. Here we depart from a common view according to which Leibniz works with a purely logical conception of possibility: we believe that it is crucial to his metaphysics of modality that possibility has a ground in essences, conceived in what may called pre-logical terms. The failure to appreciate this central dimension of his thought has led to interpretations of essences as representational or conceptual items. We propose that in order to understand the Leibnizian notion of the reality of finite essences, it is of paramount importance to pay attention to the way in which those essences depend upon God’s essence. This is a type of dependence fundamentally different from the ontological one on divine ideas, and is, in fact, prior to it. Taking seriously the distinction between the reality of essences and their ontological status will further allow us to revisit a common picture of Leibniz’s view of creation, on which the finite essences in God’s intellect and actual existing creatures are related to each other as concepts to their instantiations.

The paper will unfold as follows. In Section 2, we examine some key passages concerning the nature of possible things and finite essences. In them, Leibniz presents two main theses, namely that essences (or possibilia) are located in the intellect of God, and that the reality of essences is grounded in, or derived from, the infinite essence of God. In Section 3, we critically discuss the tendency in recent scholarship to downplay, if not ignore, the second of these two theses. Section 4 introduces our new interpretation. We argue for the importance of making a firm distinction between questions concerning the ontological status of essences and questions concerning the reality of those essences. With regard to the former, essences have objective being in divine ideas. Yet, for Leibniz, finite essences also come with different degrees of reality in virtue of being limitations of the divine essence. In fact, the notion of essences as real or as having reality is, as we shall see, presupposed by the conception of them as having objective being in the divine intellect. Section 5 argues that a certain conception of the grounding role of space in geometry is of crucial help in understanding the dependence of the essences of possible things on God. Section 6 elaborates on the implications of our interpretation for understanding the act of creation. We also indicate how Leibniz can be cleared of the well-known charge that his notion of existence is equivocal.

2. The metaphysics of merely possible things

The two most important Leibnizian theses concerning the metaphysics of possible things are as follows. First, possibilia or essences have their being in the understanding of God. Second, finite essences involve reality or perfection in different degrees in virtue of being grounded in (the essence of) God. Both theses can be found in texts from different periods of Leibniz’s philosophical career, which makes it unlikely that there is some kind of development from one thesis to the other. In this section, we shall first take a look at some of the relevant passages in which Leibniz formulates these theses. The first thesis has dominated scholarship to such an extent that the importance of the second thesis has not been properly recognized, although it is actually the more fundamental one.

In the Discourse on Metaphysics and the ensuing correspondence with Arnauld, Leibniz famously frames his account of substances, creation, and possible things in terms of complete individual concepts . The basic idea is that in God’s mind there is a completely determined concept of every possible individual substance. The complete concept of Adam, one of the substances belonging to the world God decided to create, contains every predicate true of Adam, and any variation in that concept would result in a distinct complete concept of a different possible individual. In April 1686, Leibniz writes to Arnauld:

There is a possible Adam whose posterity is such and such, and an infinity of others whose posterity would be otherwise. Isn’t it true that the possible Adams […] are different from one another; and that God chose only one who is precisely our own? (A II.ii, 19–20/LA, 25)

Arnauld’s main worry is that this doctrine leads to necessitarianism, but he also complains that the notion of purely possible substances escapes him:

I have no idea of these purely possible substances, that is, the ones that God will never create. […] [T]hey are chimeras we frame and […] everything we call possible substances, purely possible, can be nothing whatever but God’s omnipotence, which, being a pure act, does not allow there to be any possibility within it. (A II.ii, 36/LA, 51)

Leibniz, however, thinks that the notion of merely possible things does not lead to any extravagant ontological commitments. In his notes on Arnauld’s letter, Leibniz explains that he agrees that “there is no other reality in the pure possibles than the one they have in the divine understanding” ( A II.ii, 51/ LA , 73). He expands on this claim in his subsequent reply to Arnauld:

In order to call something possible it is enough for me that a concept can be formed of it, even if it would only be in the divine understanding, which is, so to speak, the land of possible realities. […] [I]f we wanted to reject pure possibles absolutely, we would destroy contingency and freedom. For if there were nothing possible but what God has in fact created, what God creates would be necessary[.] (A II.ii, 79/LA, 109)

This passage seems to offer a clear expression of the aforementioned first main thesis concerning possibilia. Even though the notion of a complete individual concept central to the Discourse seldom explicitly appears in Leibniz’s later texts, the tenet that possible things have their being in the divine understanding never loses any of its importance. Instead of the notion of complete concepts, Leibniz later uses the notions of (divine) idea and essence to describe the realm of possibilia: God’s creative act requires that there are ideas of finite individual essences in his understanding. Like complete concepts, ideas of individual essences of possible creatures — as well as eternal truths based on relations between those ideas — have being in, and are dependent on, the understanding of God.

Given divine omniscience, this kind of view is certainly reasonable: as everything (even the merely possible) is known by God, God must have an idea of every possible individual essence. The first main thesis yields an account of the ontology of finite essences: they are given, as it were, a metaphysical location in the divine intellect (“the land of possible realities”). In this way, a theocentric metaphysics such as Leibniz’s can, as Robert Adams (1994, 180) has noted, avoid the problematic features of genuine or robust Platonism.

Such a focus makes it natural to take Leibniz’s talk of possibilia as real simply to mean that they have a mode of being and a location in the divine intellect. The problem is that this fails to capture the sense of reality at work in the second main thesis, according to which the reality of finite essences is ultimately grounded in God’s infinite reality. To begin with, it is central here that the reality of finite essences derives from the entire reality of God and not only from the divine intellect or omniscience, which is just one of the divine attributes — God is the most perfect or real being, the ens realissimum, and thus necessarily has all perfections. In the preface to the Theodicy, Leibniz offers us a piece of philosophical poetry to drive the point home: “The perfections of God are those of our souls, but he possesses them in boundless measure; he is an ocean, whereof to us only drops have been granted” (G VI, 27/H, 51).³ As necessarily limited or bounded, creatures have some degree of God’s absolute perfection. It should further be noted that the idea of perfection or reality as coming in degrees clearly differs from that of having being in the divine intellect, which is something an essence either has or lacks — either it is or is not cognized by God.

While distinct from the first main thesis, the view of God as the source or ground of the reality of finite essences is still closely connected to it. Consider the following sections of the Monadology :

§43. God is not only the source of existences, but also that of essences insofar as they are real, that is, or the source of that which is real in possibility. This is because God’s understanding is the realm of eternal truths or that of the ideas on which they depend; without him there would be nothing real in possibles, and not only would nothing exist, but also nothing would be possible.

§44. For if there is reality in essences or possibles, or indeed, in eternal truths, this reality must be grounded in something existent and actual, and consequently, it must be grounded in the existence of the necessary being, in whom essence involves existence[.] (G VI, 614/AG, 218, emphases added)

The reference to God’s understanding and divine ideas (in §43) may seem to square well with the first main thesis. Yet the way in which Leibniz elaborates his view (in §44) suggests something stronger: instead of emphasizing the dependence on God’s understanding Leibniz claims that essences can have reality only if they are grounded in the actual necessary existence of God. God’s existence is, of course, a necessary presupposition of the existence of God’s understanding, but this is not the point. Leibniz is not so much concerned with the ontology of possibilia — with the way in which they exist — as with the ground of possibility: the space of creaturely possibilities must ultimately be determined by the actually existing necessary being . This means that finite essences, in addition to being ontologically dependent on the divine ideas , have reality derived from God as the fundamental actual entity. ⁴

Finite essences thus depend on God in two ways: not only as residing in the divine understanding but also as directly related to the infinite essence of God, the foundation of their reality (A VI.iv, 1635/SLT, 30–31). In what follows, we shall further elaborate this distinction and also dispel the impression that Leibniz’s talk of the reality of essences is ambiguous — that he is speaking of essences, on the one hand, as real in the sense of having being in the divine intellect, and, on the other, as real in the sense of expressing the infinite perfection or reality of God in limited ways. We shall argue that the latter is the central import of Leibniz’s talk of the reality of essences — even in passages, which at first blush are concerned with the location of possibilia in the divine intellect.

Unfortunately, in discussing Leibniz’s theory of possibilia, commentators often downplay or even completely ignore the second main thesis. This has led to a distorted picture of his position. Not only should the second thesis be taken seriously, but it constitutes the very basis of Leibniz’s metaphysics of modality. In fact, we surmise that the idea of essences as real in the sense of deriving from God’s reality (as articulated in the second main thesis) is also critical to a proper assessment of the first main thesis.

3. Representationalist approaches

As already noted, the view that possibilia, essences, or eternal truths have their being in the understanding of God can be seen as providing an alternative to robust Platonism. The idea that essences reside in the mind of God is, of course, in itself nothing new — it can be traced all the way back to Augustine and was, in different forms, accepted by several scholastics. According to one traditional line of interpretation, Leibniz espouses what we could call a representationalist version of this idea, leading to a decidedly deflationary understanding of finite essences. Most recently, such a reading has been defended by Ohad Nachtomy:

According to Leibniz, the platonic realm of essences and intelligible entities becomes a realm of pure logical possibilities. […] [This] signifies a crucial turn in the history of the notion of possibility. Possibilities need no longer be seen as entities subsisting in God; they need no longer be seen as some type of shadowy entities at all. Rather, Leibniz [sees] […] possibilities […] as mere thoughts in God’s understanding. With this deflation, the very notion of intelligibility is transformed as well: from its platonic sense of true Being to that which can be understood by a perfect mind — regardless of whether it exists or not. (Nachtomy 2017, 69)

To say that the realm of possibilities is a “realm of pure logical possibilities” means that possibility merely requires the absence of formal contradiction. Possibilities arise through a combinatorial process, whereby simple concepts are combined into complex ones — ultimately into complete individual concepts — in accordance with the principle of non-contradiction.

Nachtomy does acknowledge that there is a sense in which the ground of possibility goes beyond logic: as he reads Leibniz, God arrives at simple concepts by reflecting on the simple forms or attributes that constitute the divine essence. In this way God’s attributes may, as Nachtomy puts it, “be seen as the material or the actual basis out of which possibilities arise in his mind by virtue of God’s mental combinations and reflections” (2007, 23). The ground of possibility is nonetheless purely logical in that once the simple concepts are in place, possibility is only a matter of combinatorics, of absence of formal contradiction.⁵ This is why the realm of possibility is to be understood as a mere “conceptual realm” (Nachtomy 2017, 71): Leibniz’s frequent talk of essences should not be taken at face value, for essences (or possible things) are to be reduced to — or identified with — concepts.⁶ When Leibniz characterizes finite essences as limitations of God’s essence, all this means is that possibilia are built up from simple concepts derived from the divine attributes.

It may be thought that the doctrine of complete concepts lends support to such a reductivist approach to essences, as the former can be taken to imply a picture of God’s creation as a matter of choosing between descriptions of possible worlds, constituted by complete concepts. God has conceptual representations or blueprints of possible worlds in his understanding, and the actual world corresponds to one of these representations — the one describing the best possible world — so that actual things are to be seen as instantiations of divine concepts. What is “located” in God’s mind, on this picture, are basically just representational items.

Yet it is anything but clear that Leibniz’s notion of complete concept licenses a representationalist reduction of possible things or their essences. We have already seen that he often frames his views of substances, creation, and possible things by stressing the notion of essence without adding any deflationary or reductivist qualifications. It is true that Leibniz often describes God’s intellect as the realm of ideas, but it is important to keep in mind that ideas, for Leibniz, are in the first place immediate objects of thought, as he explains in the New Essays: “If the idea were the form of the thought, it would come into and go out of existence with the actual thoughts which correspond to it, but since it is the object of thought, it can exist before and after the thoughts” (A VI.vi, 109/RB, 109). It is thus misleading to characterize, as Nachtomy does, possibilities or essences as “mere thoughts” of God.

We are not the first to note the limitations of reductivist readings of essences. Samuel Newlands (2013, 165n26) is overtly critical of attempts to “flatten Leibniz’s ontology on this point.” He tries to do justice to the central place of essences in Leibniz’s thinking about modality, while at the same time steering clear of committing him to genuine Platonism. Newlands argues that “essences are the objective beings of God’s ideas,” which he takes to be equivalent to saying that essences are the intentional objects or representational contents of divine ideas (2013, 165). It is crucial to Newlands’s point that merely possible essences are, as he puts it, “purely intentional objects” (2013, 165), that is, that they have mere objective being and not, to use the traditional terminology, formal being, or actual existence. The difference from the reductivist interpretation is that essences are intentional objects of God’s thoughts and not, as they are for Nachtomy (2017, 69), “mere thoughts in God’s understanding.” Without committing Leibniz to genuine Platonism, we are nevertheless offered an ontology of essences: they have a way of being in the divine understanding.

On the basis of such a minimalist reading Newlands ascribes a bipartite grounding thesis to Leibniz: (i) finite essences are truth-makers for modal propositions; (ii) as essences are purely intentional objects of divine ideas, the latter constitute the ontological ground of the former, which means that “divine ideas provide the reasons in virtue of which essences have their reality” (Newlands 2013, 172). On this picture, divine ideas are the ultimate explanation for finite essences, for the space of possibilities is determined at the level of divine ideas — the ground of possibility lies, as it were, in divine psychology. Essences are real insofar as they have an ontological status in the divine intellect — indeed, Newlands explicitly talks of the “ontological status or ‘reality’” of essences (2013, 165). His interpretation can thus also be characterized as representationalist in that it is based on the first main thesis alone — that essences reside in the divine intellect.

Although we also find essences crucial to Leibniz’s modal metaphysics, we believe that Newlands takes this idea in the wrong direction. In our view, the right way to proceed is to take the second main thesis seriously. That is, we propose that finite essences themselves — and not only simple concepts, as Nachtomy’s logical approach would have it — have what we shall call a pre-logical ground in the divine essence.⁷

In attributing a purely logical conception of possibility to Leibniz, commentators typically draw on his assertion that “all truths that concern possibles or essences and the impossibility of a thing or its necessity (that is, the impossibility of its contrary) rest on the principle of contradiction” (A VI.iv, 1445/AG, 19) so that “anything that, in itself, implies no contradiction” is “possible in its nature” (A VI.iv, 1447/AG, 21). Such a reading is far from obvious, however. The scholastics widely shared the idea that absence of contradiction is sufficient for possibility. Yet this is not to say that all medieval thinkers subscribed to a purely logical conception of possibility: the key issue concerned the basis of contradiction, namely whether it is purely formal or instead metaphysical in nature. A prominent case in point is Aquinas. As John Wippel (1984, 168) explains, although Aquinas sometimes expresses the most basic kind of possibility (absolute possibility) “by appealing to the absence of incompatibility between the terms which describe such a thing, the possibility in question is not merely linguistic, nor merely logical, but ontological.” The ultimate ground for possibility “is the divine essence itself insofar as it is viewed by God as capable of being imitated in a certain way” — the divine essence “accounts for the fact that a possible is not self-contradictory and is therefore possible in the absolute sense.”

We take Leibniz’s second main thesis to express broad agreement with Aquinas on this score: the divine essence is ultimately what determines the space of possibilities.⁸ However the details of Aquinas’s own account are to be spelled out, we further take it that the grounding of the reality of essences in the divine essence is not for Leibniz a matter of offering an ontology of finite essences. This marks our second point of disagreement with Newlands: not only are essences not fundamentally representational or psychological, but they are not fundamentally existents at all.

This may sound surprising. It is natural to think that rejecting a purely logical conception of possibility in favor of grounding modalities in essences implies a commitment to some kind of ontology of essences: we easily construe the alternative to a purely logical conception of modalities in terms of a need for truth-makers of modal propositions, where a truth-maker is understood as an existing entity that makes a proposition true. Traditionally there was, however, a different view of the real ground of possibility. On this view, the relevant notion of reality was what can be called pre-ontological. We believe that this sort of approach underlies Leibniz’s second main thesis. Understanding this point requires a firmer grip on the notion of reality itself.

4. The reality of essences

We hold that there are two orthogonal metaphysical dimensions that are relevant in understanding Leibnizian essences: the grade of reality and the ontological status. When discussing the former — the reality of essences — Leibniz is not concerned about whether they have merely objective being in God’s understanding, or whether they instead have some mind-independent being, some sort of formal being in a Platonistic realm of essences. Rather, his focus is on the nature and determination of whatever has objective being in divine ideas and what also in some cases acquires formal being, or actual existence, in the created universe.

We should thus resist the temptation to think of objective being in terms of modern notions of mere representational content or purely intentional objects. God’s understanding does not conjure finite individual essences out of nowhere: God’s infinite essence is the ultimate source of finite essences, of all limited possibilities. In this way, essences are metaphysically prior to God’s ideas of them; essences are realities that acquire an objective mode of being in divine ideas. This proposal obviously requires some unpacking. We shall first outline the general distinction between reality and ontological status, and then consider more closely the role of the notion of reality in Leibniz’s account of the relation between finite essences and God.

5. The nature of limitation

In this section, we aim to explicate the nature of the limitation relation. Thereby we will come to better understand Leibniz’s argument for the claim that finite essences depend upon God’s essence for their reality.

As we saw, even the logical approach acknowledges the importance of the idea that finite essences are in some sense limitations of God, but it is far from clear that it can give an adequate account of what limitation involves. As Sebastian Bender (2016, 140) has shown, mere logical means are insufficient to explicate the limitation relation.¹⁷ A finite individual can only either completely lack or completely possess the perfection expressed by some simple concept, depending on whether that simple concept is either denied or affirmed in the complete concept of that individual. Bender’s (2016, 143) own response to this problem is to try to amend the logical approach by adding a pre-logical level to the thought-processes of God: before the combinatorial process begins, God’s intellect produces limited versions of his own attributes. This is a crucial insight, but in our view it should be taken a step further. Without denying the importance of combinatorial ideas in Leibniz’s views concerning the nature of thought, it is actually unclear whether even a metaphysically enriched combinatorics of Bender’s sort is enough to capture the core of Leibniz’s notion of essence.

The logical approach relies on what may be called an aggregative conception of essence, a view of both divine and creaturely essences as ultimately consisting in collections of attributes or perfections. But it is difficult to see how this could be the fundamental story about God’s essence, which is supposed to be simple. Indeed, in some places Leibniz explicitly emphasizes God’s simplicity or unity in characterizing the relationship between finite essences and God, for instance when he famously claims that all things can be analyzed “into God and nothing” (A VI.iv, 158–59/MP, 3). The aggregative view is also unable to capture what is arguably Leibniz’s considered view of the essence of a substance as what he calls a law of the series — that is, as the explanatory ground of various features (or properties) belonging to the substance rather than a mere collection of such features.¹⁸

We believe that to make sense of creaturely essences as limitations of God’s essence it is not enough to have a pre-logical level of limited predicates , which are then combined by logical means into finite essences. Rather, we need a pre-logical or pre-combinatorial account of how finite essences themselves directly result from or are limitations of God’s essence. Here we would like to draw attention to an important, but largely neglected, analogy Leibniz uses throughout his career in order to explicate the relationship between the infinite essence of God and finite essences: the reality-dependence of finite essences on the infinite essence is to be considered in significant respects analogical to the relation between space and geometrical figures . ¹⁹ A notable example is “De abstracto et concreto” (1688), where Leibniz elaborates the analogy in an attempt to dispel the worry that he risks ending up in Spinozism:

[A]s all the reality of creatures is in God, it seems to follow that all creatures are in God. But […] the reality of creatures is not that which is absolutely in God but that which is limited, which in fact forms the essence of the creature. This can be illustrated with the image of space and a body: the extension of space and that of a creature [i.e. a body] differ in that the extension of space is in itself absolute, unbounded, indivisible, without any change[.] […] In contrast, the extension of a body is limited with respect to all of its modes. (A VI.iv, 990)²⁰

Leibniz’s use of the analogy should not come as a surprise. There can hardly be any doubt that he was familiar with the suggestion that thinking about the way in which infinite extension gives rise to geometrical figures can help us to understand how God’s essence is related to finite creaturely essences: after all, this idea was prominent among his contemporaries, especially Spinoza and Malebranche. ²¹ Leibniz even explicitly defends the latter’s claim that God is “being in general” by saying that by this Malebranche “did not understand a vague and indeterminate being, but absolute being, which differs from particular limited beings as absolute and boundless space differs from a circle or a square” ( RML , 481/ W , 556).

Admittedly, one could complain that what Leibniz offers us is just an analogy, a model. At the same time, it is also a very intuitive model of some of the key features of Leibniz’s view of divine and finite essences and their relationship. Space in itself is to be conceived of as infinite, unified, and indivisible. As the ground of the possibility of an unlimited number of geometrical figures, it is — prima facie paradoxically — both in an important sense simple and infinitely abundant. The abundance means that everything geometrically possible is contained in the infinite space in the sense of being constructible in it, which is about delimiting the space rather than adding something to it. For instance, a triangle can be produced because the Euclidian space can be delimited by devising three intersecting lines, and this construction procedure fixes the essence of a triangle from which all its properties follow.

In this way, the geometrical model allows us to take seriously the idea that the infinite essence, conceived of as unitary and simple, can be the source of a multitude of finite essences via a process describable as limitation — the idea that finite essences can be analyzed “into God and nothing.”²² Moreover, the products of this process, finite figures, are not conceived of as collections of features, but rather are determined by a construction procedure from which other properties follow, i.e. something close to the conception of essence as the law of the series.

The analogy also throws light on why the question concerning reality-dependence is so important to Leibniz — why he thinks that the nature of finite essences needs to be explained via the essence of God. This involves what can be called the unity of geometry. Not only must there be a single grounding space for the whole variety of geometrical objects — or one space for one geometry, as we might prefer to say, knowing that there are many possible geometries — but all geometrical objects are thoroughly interconnected: they all must conform to the constraints, principles, or laws of the single space. Conversely, we may say that precisely because they display such a deep interconnectedness, all geometrical figures are of the single space. The geometrical model thus makes it natural to infer from the interconnectedness of essences to a common source of their reality, or as Leibniz says, the reality of both essences and existences “can be sought in but one source, because of the interconnection among all of these things” (G VII, 305/AG, 152).

Leibniz’s claim that essences as limitations have different degrees of reality, where this is understood as having an “amount of essence or reality” (G VII, 303/AG, 150), is easily read as suggesting a scalar picture of the metaphysical hierarchy, where each finite essence corresponds to some quantum of God’s essence. Yet the geometrical analogy offers a more sophisticated way of understanding metaphysical “density.”²³ In geometry we do not equally focus on all possible geometrical figures: interesting theorems can be proven of such things as circles and triangles, but there are also endless varieties of shapes of which there is little to be said. The significance we attribute to circles and triangles has arguably to do with the fact that they simply are more important as geometrical objects, revealing, or expressing, more of the nature of space than some other objects, and as such they have a higher degree of reality or contain a greater “amount” of the essence of space.

How then does the analogy help with the worry that if “all the reality of creatures is in God” then “creatures are in God”? We think that, for Leibniz, being the ultimate source of the reality of geometric figures does not endanger the infinite nature of space itself: something finite and limited is possible by virtue of space, but this does not take anything from space — space as such does not become limited or diminished. This also suggests that it is not so clear (pace Newlands) that a more robust form of grounding of possibilities in God means that God must exemplify possible creaturely properties. The possibility of, for instance, triangular figures certainly does not require that the infinite space exemplifies triangularity. Still, the infinite space is what grounds the possibility of triangularity. Although this leaves leeway for interpretation, the analogy clearly shows how something infinitely rich can ground the possibility of an endless variety of finite things without itself exemplifying their properties.

6. Creation and the nature of actual existence

We have argued for the need to distinguish two kinds of dependence of finite things on God. The fundamental one (expressed by the second main thesis) is reality-dependence, the dependence of finite essences on the infinite essence of God. The other one (expressed by the first main thesis) is the dependence of finite essences on God’s understanding, that is, on divine ideas, which gives us an account of the ontological status of essences regardless of whether they are actualized or not.

There is of course a further way in which finite things depend on God: creatures must be created, they could not actually exist without the necessarily existing infinite being having “produced” them. It is important to note that this type of ontological dependence of creatures on God — the way creatures depend for their existence on God — presupposes the reality-dependence of finite essences on God. There could not be actually existing creatures without prior finite individual essences, because divine creation is not blind: God must have something from which to choose what to create.

The priority of reality-dependence deeply affects the way in which we understand the nature of creation. If we regard the realm of essences as merely conceptual (or representational), we are naturally led to a conception of that realm as in need of some kind of activation by God, or as Nachtomy puts it: “[A]ctualization requires that a unique and well-defined course of action, corresponding to a possible individual, be given power to act and thereby make it actual” (2007, 132).²⁴ In this picture, actual existence has the following meaning: to actually exist is to be an essence to which power or agency is added, which turns an abstract essence into an agent.

Yet such a reading sits ill with textual evidence. Take, for example, the two central Leibnizian notions, the law of the series and primitive force. On the representationalist approach, the law belongs to the abstract level, the primitive force to the concrete. However, Leibniz himself instead identifies the law of the series with the primitive force: “The essence of substances consists in the primitive force of action, or in the law of the sequence of changes” (A VI.3, 326/L, 155, emphasis added).²⁵ Indeed, it is the universe itself — the collection of substances — that God brings out of possibility, as Leibniz insists in a letter to Clarke: “properly speaking, there is but one decree for the whole universe, whereby God resolved to bring it out of possibility into existence” (G VII, 407/LC, 78).²⁶

Nachtomy (2007, 129) holds that such passages involve confusion. But in our view, there is nothing problematic here: the absence of a distinction between an abstract level of essences and a concrete level of actuality is just what one should expect. Recall that the notion of the reality of essences is not to be seen as an attempt to characterize their ontological status, for reality derived from the infinite essence is what constitutes a finite essence as something possible that can have any ontological status in the first place. In actualizing a finite essence, God does not consider and compare mere conceptual complexes. God considers possible substances — realities or essences — he is about to create, akin to the way for Descartes the triangle itself is in our minds when we perceive or think about it (CSM II, 44–45). In creating one of the possible worlds God does not add some new feature (e.g. power) to essences, but gives them a new ontological status. One and the same reality is first a mere possible substance and after creation an actually existent substance.

In a remarkable passage Leibniz inquires how possibilia differ from actual existents. He begins by claiming that “an existent is an entity, i.e. a possible, and something else,” which may at first sight suggest a view of actualization as involving adding something to an essence. Consider, however, what he says next:

“[E]xistent” is what would please some mind, and would not displease another more powerful mind, if minds of any kind were assumed to exist. So […] there is said to “exist” that which would not displease the most powerful mind, if it should be assumed that a most powerful mind exists. (A VI.iv, 763/P, 65–66)

Not unsurprisingly, many have found mysterious the claim that existence consists in pleasing God. It is tempting to assume that God’s actualization of an essence must follow from the fact that the essence pleases God. But Leibniz no doubt finds our common sense way of thinking about willing to do something and then doing it inapplicable to God. However the exact details are to be worked out, one benefit of trying to take literally Leibniz’s claim is that it throws light on what a change in ontological status amounts to. To say that existence is about pleasing God is simply a figurative way of saying that the actualization of a finite essence consists in its coming to stand in a completely new relation to God, rather than in its acquiring some new feature .

One virtue of adopting such a relational interpretation of actualization is that it allows Leibniz to fend off the charge according to which he endorses an equivocal notion of existence. Bertrand Russell (1900, 174) famously argues that in formulating the ontological argument for God’s existence, Leibniz holds that existence is a perfection and thus included in the divine essence. In contrast, in the case of creatures existence is a second-order notion: a created substance exists when its individual concept is instantiated. Yet, on the relational interpretation, fundamentally the same notion of existence is applicable both to creatures and to God. For both, existence can be seen as a status of essences that depends on standing in a special kind of relation to God.²⁷ The difference is that in God’s case nothing beyond the infinite essence is needed: because the divine essence is in some sense self-related (pleasing to itself, as it were), it necessarily exists by itself. In contrast, the existence of creatures requires that they are related to God and thus to something beyond their own essences.

7. Conclusion

The idea that creaturely essences have their metaphysical location in the divine understanding is part and parcel of well-established Western philosophical theology. This thesis plays an important role in Leibniz as well. In this paper, we have emphasized that Leibnizian essences are not merely conceptual or representational items residing in the divine mind but rather possible individual substances.

In order to understand Leibniz’s position we must carefully distinguish between questions concerning, on the one hand, ontological status, and, on the other, reality. The requirement of reality has to do with the fact that the ground of possibility cannot be understood in purely logical or formal terms; instead, it must be understood metaphysically. Essences have reality prior to God’s ideas of them, and their reality is derived from the unlimited reality of the infinite essence. On this view, essences are realities that acquire objective being in God’s understanding. To say that the reality of essences is prior to God’s ideas of them does not thus alter the view of Leibniz’s basic ontological stance toward finite essences — it does not commit him to robust Platonism. Even though their reality is prior to God’s ideas, only the ontological status of having objective being in the divine mind pertains to essences as possibilia. In creation, it is the ontological status of essences that changes into actual existence. Thereby we can make sense of an intriguing, but lamentably often overlooked, aspect of Leibniz’s theory of creation: the idea that one and the same thing is first a mere possibility but after creation an actually existent substance.²⁸