Abstract: I investigate the meaning and significance of Spinoza’s elusive concept of “expression”. I do so by situating expression among his canonical relations of conception, causation, and inherence. I argue that, for Spinoza, expression necessarily corresponds to what is sufficient for conception, but implies neither causation nor inherence. This correspondence with sufficient conditions on conception and the pulling apart of expression from causation and inherence has important consequences for our grasp of the interconnections among Spinoza’s key metaphysical relations. But it also has profound implications for our understanding of the essential structure of Spinoza’s ontology itself, and for the proper assessment of his rationalism. I explore these consequences by explicating Spinoza’s assertion that substance and each of its attributes are “conceived through themselves”, and by demonstrating that, on his view (though contrary to that of most commentators), the relation of conception is not to be accounted for in causal terms. A systematic treatment of the expression relation sheds new light on these issues. The result is a view of the underpinnings of Spinoza’s metaphysics that is as surprising as it is compelling.Much recent work on Spinoza’s metaphysics seeks to explain the nature of the fundamental relations that structure his ontology. Most attention by far has been trained on Spinoza’s three canonical relations of metaphysical dependence: conception, causation, and inherence. Indeed, charting the interconnections among these three relations has been one of the chief goals — and ongoing success stories — of contemporary Spinoza scholarship. But there is another relation whose presence in Spinoza’s system is equally prominent, yet whose status remains conspicuously uncertain: “expression” (exprimere). My chief aim is to show that this thesis applies to the complete range of cases in which Spinoza invokes the concept of expression. On this reading, for example, Spinoza holds that a given attribute expresses God’s essence just in case conceiving of that attribute is sufficient for conceiving of God’s essence; a given mode expresses the attribute under which it falls just in case conceiving of that mode is sufficient for conceiving of the essence of God through that attribute; and the mind and the body express “one and the same” individual just in case conceiving of the mind and of the body is sufficient for conceiving of the essence of that individual.These themes are connected with a second Spinozistic commitment I’ll attempt to explicate: the autonomy of conception and expression from the other key relations that drive explanations within the context of Spinoza’s metaphysics. If we take seriously thesis (1) as an analysis of expression, we see unambiguously that the relations of conception, on the one hand, and causation and inherence, on the other, come apart. For Spinoza, that is, all connections of causation and inherence admit of conceptual articulation, because all such connections are conceptual connections. But not all conceptual connections are connections of causation or inherence, and in fact, in many cases, connections of the latter kinds holding between certain relata are strictly orthogonal to the conceptual connections holding between those same relata. Hence it is not the case thatThe plan is as follows: In section 2, I defend thesis (1) as an interpretation of Spinoza’s notion of expression, focusing on the relation of the term ‘exprimere’ to Spinoza’s broader conceptual terminology; the import of Spinoza’s statements about the expression of attributes and modes; and what such talk reveals about the fundamental natures of, and ontological distinction between, the latter. I unfold this distinction by attending to how the meaning of claims about expression is linked to the degree of determinacy of the entities which those claims are about. This broader analysis confirms what I have represented as the underlying message of Spinoza’s claim that substance and each of its attributes are conceived through themselves: namely that the essential role of the expression relation is to exhibit determinate things — characteristic unities. In section 3, I extend this analysis by exploring the incongruities between expression, causation, and inherence. The results of this section serve to detach the notion of what it is to conceive of a determinate thing as a determinate thing from the requirement that a determinate thing must be conceived as such in virtue of independently specifiable factors involving causation or inherence. In the final section of the paper, I draw on the characterization of Spinoza’s ontology offered in section 2 and the lessons concerning the autonomy of expression derived in section 3 to account for how Spinoza both secures and constrains the role of rationality and explanation within the context of his metaphysical scheme. I end by suggesting how, on this basis, Spinoza’s rationalism, as an independent philosophical commitment, ought to be assessed.In some instances, ‘expression’ corresponds to what Spinoza would regard as necessary and sufficient for conception. This is so in the case of attributes and definitions, which express, and are necessary and sufficient for conceiving of, substance and essences, respectively. More generally, however, Spinoza implies that expression picks out precisely what is sufficient for conception. This is true in the case of modes, which express and are sufficient, but not necessary, for conceiving of substance. It is also true in relation to Spinoza’s standard terminology for conceptual claims, which, as we will see below, may themselves be parsed as stating sufficient conditions on conception. Spinoza treats these sorts of claims — e.g. that ‘x is conceived through y’, or that ‘x requires the concept of y’ — as materially equivalent with the claim that ‘x expresses y’. These facts provide a clue as to what Spinoza thinks “expression” really is: what his metaphysical analysis of the relation would be. This analysis, abbreviated in (1), could go as follows: for any object x and property φ, φ expresses (the essence of) x just in case: (i) x is φ and (ii) there is a determinate conception, ψ, such that the parameters for individuating ψ correspond to the parameters for individuating φ. If this analysis is correct, then φ’s being sufficient for conceiving of x (in virtue of its isomorphic relation to a particular conception of x) is (partly) constitutive of what it is for it to be an expression of x (the other constitutive feature being that φ is genuinely a property of x). The necessity ascribed to the biconditional in (1) is therefore metaphysical necessity, and one could speak of a “coextensiveness” between the relations of x’s expressing y and x’s being sufficient for conceiving y analogous to that between the properties has a heart and has a kidney: there is never a case when one would predicate one of these relations or properties of something without presupposing the other. Nevertheless, (1) should not be understood as stating that everything that is true of expression is true of conception, and vice versa. There can exist a conception of x, ψ, which does not correspond to an expression of x, φ; in that case we would not say that the biconditional in (1) holds, since φ is not sufficient for ψ.Hence the notions of “involving”, “being conceived through”, and “requiring the concept of” all share the sense of ‘being sufficient for conceiving of’. These notions are also parallel with the notion of something’s “not being able to be conceived without” another thing. Thus consider 1d5 and 1p15, which respectively state that modes are “conceived through” and “cannot be conceived without” God. The parallel import of these texts implies the equivalence of these two ways of stating the conception relation. This is significant in light of 2p49d, where Spinoza writes that “to say that A must involve the concept of B is the same as to say that A cannot be conceived without B”. Given the equivalence just observed between ‘cannot be conceived without’ and ‘conceived through’, Spinoza must take ‘conceived through’ as equivalent with ‘involves’; and given the interchangeability of ‘conceived through’ with ‘requires the concept of’, he must take the latter notion as also interchangeable with ‘involves’. Thus Spinoza evidently sees ‘is conceived through’, ‘cannot be conceived without’, ‘requires the concept of’, and ‘involves’ as all denoting the same conceptual relation. Moreover, because Spinoza plausibly treats ‘expresses’ as coextensive with ‘involves’, he must regard ‘expresses’ as coextensive with the other formulations for the conception relation as well. Thus the interchangeability of these various formulations for the conception relation, together with the coextensiveness of the verbs involvere and exprimere, indicates that, insofar as Spinoza’s talk of expression strictly covaries with his talk of conceptual relations more generally, the relation of one thing’s expressing another thing may be viewed as coextensive with the relation of one thing’s being sufficient for conceiving of another thing. The scope of these terminological considerations, then, lends strong presumptive support to the view that Spinoza universally endorses thesis (1). But to substantiate this commitment, we must establish the way in which (1) informs the meaning of the fundamental metaphysical doctrines whose articulation or defense involves an appeal to the notions of expression and conception. So let’s now turn to a more direct examination of Spinoza’s texts. 1d4: By attribute I understand what the intellect perceives of a substance, as constituting its essence.Notice that, in the scholium, Spinoza reasons that we cannot infer that any two attributes constitute distinct substances — despite our ability to conceive of them as really distinct — because each attribute is conceived through itself. The idea behind this inference might be as follows: Any two attributes, A and B, would have it in common that they belong to one substance. But suppose that A and B were in turn distinct substances, on account of their real distinction. Then there would have to be a relation between them in virtue of which they, as independent substances, both belong to one substance. That relation would have to be such as to explain the unity of the one substance to which A and B belong. However, the relation would be one between A and B, and so also would have to be one that explained their interconnection. But this interconnection is itself dependent on the unity of the original substance, which is what the supposed relation has been invoked to explain. Thus, on pain of circularity, we cannot regard a substance’s attributes as distinct beings or substances in their own right. Once we grasp these implications, the message Spinoza wants to convey about the uniqueness of substance, or its being conceived through itself, becomes apparent. For something to be “conceived through itself”, or to be unique, is for that thing to possess a characteristic unity, to be one thing of the same nature. But I take the lesson of 1p10s to be that this notion also entails that something that is conceived through itself cannot be explained through its relations to other things, including relations between its own attributes. Thus the unity of substance, for Spinoza, is basic and is not further explained by any relations between its attributes. The nature of each attribute, in turn, is fixed by the nature of the one substance to which it belongs, of which it is a conception. What makes an attribute one attribute, one conception, is the nature of its contribution to (the conception of) the one unified substance. And this contribution is, in fact, just what is embodied in the way that an attribute expresses substance.Spinoza also holds that it exhibits eternity and infinity, and for plausible reasons. A primary, or fundamentally real, element of reality — one in which all non-fundamental existing objects must be “situated” — must apply to existing objects without conceivable limit (be infinite), and the statement ‘There exists a mode m situated in A’ must be true, regardless of the time to which this statement is indexed. So each attribute, on this construal, essentially demonstrates its own necessity, eternity, and infinity. This, to me, is a plausible way of making sense of the claim that each attribute “expresses a certain eternal and infinite essence”. It is its own essence that an attribute expresses, but ipso facto the essence of substance, since the attribute is identical with the substance. Yet the story is not over until we’ve grasped the necessity of there being an infinity of attributes, an infinity of expressions, of a substance. What is behind this ground-floor assumption? I suspect that, for Spinoza, to suppose an expressionless world is simply to posit a world without necessity. The very possibility of a necessary truth, for him, rests on the connection between the concepts of a “nature” and of “existence”: a necessary being is one whose nature cannot be conceived except as existing (1d1). But to have a nature is to have attributes, and for those attributes to exist is for them to be expressed. But if a being is necessary, as the substance that is God is, then it cannot possess just one attribute, since to be just one attribute is, by definition, to be singled out from among all remaining possible attributes (1d6e). For the remaining possible attributes not to be realized would make it contingent that God possesses the one attribute that he does, and hence would make his nature — which is identical to his existence — contingent. But this contradicts the truth that it’s essential to God that God exists necessarily (1p7, 1p11). Thus, if God is a necessary being, he must be absolutely infinite; and this absolute infinity must consist in the absolute infinity of expressions, on the part of each of the substance’s attributes, of their own infinity.This result raises an important point about the dichotomy between attributes and modes. Contrary to the shape of the “metaphysical analysis” of expression I earlier proposed on Spinoza’s behalf, attributes are not properties of substance (nor are they objects, for that matter). That analysis properly applies to things which, as Spinoza puts it, exist “outside the intellect”, and the attributes, though not entirely subjective, do not “reside” independently in the world either: they are irreducibly perspectival entities. Modes, by contrast, are characterized by Spinoza as “properties” (propria, proprietates) of substance, the character of mode expression thus being more straightforwardly in line with my earlier analysis of the expression relation. Yet we’ve seen that thesis (1) perspicuously represents the thrust of Spinoza’s statements concerning the expression of attributes, in a way that fits within the general framework of the former analysis. It remains to be determined how this framework can be exploited to elucidate Spinoza’s view of what it is that modes express, and what it means for modes to express the sorts of things they do. We’ll see that there are systematic differences in the way in which attributes express substance, on the one hand, and modes express their attributes and other modes, on the other — differences which trace the very foundations of the ontological divide between attributes and modes, and which enrich the concept of “expression” itself.This last point suggests a reading of 1p25c according to which Spinoza is not there claiming: “Modes are affections of God’s attributes, and they express those attributes.” Rather, his claim would be that modes express God’s attributes insofar as they are modifications of those attributes. Thus the precise point he seems to be making in 1p25c with respect to modes — and uniquely modes — is that the notion of a thing’s constituting a certain way (modus) of being x cannot intelligibly be separated from the notion of that thing’s being an expression, φ, of x. (Compare again: for a colored thing to constitute a certain way of being colored just is, supposedly, for that thing to express its color.) Modes, considered in the technical, ontological sense, are, I’m now proposing, just what the purportedly non-technical meaning of ‘modus’ suggests they are: certain and determinate “ways” in which attributes are expressed. I insist on a rigorous construal of modes as “ways” as a means of elucidating what Spinoza means by calling modes “certain and determinate”. Spinoza’s claim in 1p25c is not, on my view, that modes are certain and determinate, full stop. Rather, I suggest, in this representative passage ‘certain and determinate’ is being predicated of modes as ways. And if my interpretation of the nature of attributes is correct, then modes, as such, are in fact less determinate entities than the attributes they express. How can this be? 1p25c is the ur-statement of the claim that modes are “expressions”, and it says that modes express God’s attributes. But Spinoza also holds that modes express other modes. For instance, the mind expresses the body (G II.204.10; 5p22), and the part expresses the whole (Ep. 36). The claim that a mode may express another mode acquires signal importance in the context of one of the most momentous claims in the Ethics: that a mode of Extension and the idea of that mode express, and indeed are, “one and the same thing” (2p7s). Any account of Spinozistic expression must explain this and the previous propositions. In fact there is a single principle underlying all these cases of mode expression. It is that the expression of modes tracks the degrees of determinacy of that which they express. The essential idea is that what is more determinate is not sufficient for conceiving what is less determinate: what it takes to conceive of the latter must outstrip what it takes to conceive of the former. Now, a way of being x must be something over and above simply being x. Conceiving of what it simply is to be x is not sufficient for conceiving of what it is to be a way of being x, but conceiving of a way of being x is sufficient for conceiving of what it is to be x. Hence a mode, as a way of being (modifying) the thing it expresses, must be less determinate than that thing itself. A fundamental tenet of Spinoza’s ontology is that the existence of one thing that is less determinate than another thing suffices to make the former thing capable of existing as a way of being the latter thing.On this criterion, then, insofar as a mode expresses the attribute under which it falls, it expresses, and is sufficient for conceiving, something wholly determinate, while the mode’s nature is less-than-wholly determinate itself, being a way in which its attribute is modified. The mode, in contrast to the attribute it expresses, is a way in which the nature of substance may be characterized or brought under a description of a given sort. Next, insofar as a mode expresses the essence of another mode, the first mode expresses something that is less determinate than the attribute under which both modes fall, but in expressing the second mode, this first mode is less determinate still then the second mode that it expresses, being a way in which the second mode may be characterized. And so the pattern unfolds, along a dimension of lessening degrees of determinacy, with each mode being a less determinate modification of the mode it expresses.The key factor required to resolve this difficulty, and to display how the claim of 2p7s conforms to the principle of mode expression just elaborated, is, I suggest, Spinoza’s notion of a finite thing’s “actual essence” (essentia actualis). In 3p7&d, Spinoza links this notion to the pivotal concepts of a mode’s “power” (potentia) or “striving” (conatus), and equates all three notions with a mode’s determinate and proprietary pattern of causal activity (cf. 1p36d). Crucially, the notion of an actual essence is characterized in attribute-neutral terms. So, one theory on which the puzzle of 2p7s is resolved would be that the mind and the body express an attribute-neutral entity: the actual essence of a human being. A “conflation” of wholly distinct, wholly determinate attributes would hence be avoided. What explains Spinoza’s talk of the mind’s and the body’s being “one and the same thing”, on this theory, would be that the actual essence of a human being owes its manner of determinacy precisely to the relationship that exists between a certain mind and a certain body, which themselves constitute separate ways in which such determinacy is situated, and expressed, in different attributes. Thus the actual essence of the human being would consist of that pattern of causal activity existing uniquely in virtue of the relation constituted by its mind’s being the idea of its body (2p13). Though the mind and the body are embedded in separate attribute contexts, the relationship between them is definitive of the characteristic pattern of causal activity that constitutes a human being’s (attribute-neutral) essence: outside of that precise relationship, such activity would conform to no identity. Hence, a mode of Extension and the idea of that mode are “one and the same thing” just because, absent the characteristic relationship between the former, parallel modes, there would be no “one and the same thing” to speak of.What, now, of Spinoza’s related but distinct claim, that the mind is an expression of the body? Does this proposition answer to the same principle earlier put forward, that a mode that expresses another mode is always less determinate than the mode that’s expressed? It is plausible that it does. Spinoza writes specifically that the mind, or an idea of the mind, “indicates or expresses [indicare vel exprimere]” a “constitution” or determination of the essence of the body (Ethics part 3, General Definition of the Affects, G II.204.9–10), or simply that it expresses the essence of the body itself (5p22). What is the essence of the body? Spinoza spells this out in a textual interlude on corporeal individuation known as the “Physical Digression” following 2p13. In lemma 5 of this discussion, Spinoza states that the essence of an individual body is constituted by a precise “ratio” (ratio) of motion and rest which is sufficient to determine a body as the individual thing that it is as long as the ratio is preserved, regardless of whatever other physical changes (such as loss or acquisition of parts) affect the body in question. This, then, will be the principle that determines the essence of a certain human body, an essence that, as we’ve said, will, in addition to the essence of a human’s mind, express a human’s actual essence, the pattern of causal activity determined by the relation between the respective essences of the human’s body and mind. But the mind of the human being, Spinoza goes on to state in the propositions that follow the Physical Digression, represents the essence of the human body in such a way that it perceives the affections which follow from the latter essence in addition to the affections of other bodies which affect its body (see 2pp15–19). Spinoza therefore characterizes the mind as a highly complex, confused, and diffuse representation of that which is in fact decidedly more determinate: a precise ratio of motion and rest that underlies the pattern of changes that accrue to the human being’s body in its interaction with other bodies. The human mind, as a complex and perpetually reconfigured idea, expresses, and is sufficient for conceiving of, something that is intrinsically more determinate and precisely delineated. The mind is sufficient for conceiving of this more determinate thing because the parameters for individuating the mind’s content, though comparatively indeterminate, nevertheless correspond to the parameters for individuating the nature of the body it represents: indeed such correspondence is, by hypothesis, what is required for the mind properly to be regarded as an idea of the body.(B’) A mode can express, and be sufficient for conceiving of, another mode.Principle (I) directly explains the character of mode expression — why conditions (A’)–(C’) obtain. Principle (II), in turn, underwrites the character of attribute expression, and the applicability of conditions (A)–(C). The fundamental distinction between attributes and modes, then, can be characterized as one between the sort of entity that is wholly determinate — that which, in our conceptions of existing objects, expresses, and is sufficient for conceiving, what is ineradicably fundamental in whatever it is we conceive — and what is, in varying degrees, less determinate, the existing objects that express, and are sufficient for conceiving, the ineliminable features of their existence in ways that enable those features to be diversely characterized.We’re about to see, however, that Spinoza’s concept of expression actually answers to no such demands. This can be appreciated only once the nature of the connection between expression, one the one hand, and causation and inherence, on the other, is properly understood. I fulfill this aim now. Once this task has been accomplished, we’ll be poised to locate the basis of Spinoza’s metaphysics of expression in his distinctive understanding of the nature of metaphysical necessity, and to assess his rationalism from a different angle.I believe these commentators are misguided, that (2) and (3) are false. It is not only the case that expression cannot be explained by causation or inherence; it’s also true, crucially, that what gets expressed when one thing expresses another thing are not necessarily causal facts about that thing or facts about what inheres in that thing. The expression relation tracks something more basic, namely, the determinate nature of a thing, its characteristic, essential unity. If one removes the account of what causes a thing to have the properties that it does, or of what properties inhere in it, one is still left with this essential unity. This does not make causal explanations or the enumeration of a thing’s properties irrelevant to any account of the thing. But it does entail a denial of the assumption that what it is for a thing to be what it is is not distinct from what causes it or what properties it has. I’ll substantiate these claims now by showing that, on Spinoza’s view, one thing’s expressing another thing doesn’t imply that the first thing is caused by or inheres in the second thing. In the following section, I’ll point out how facts about what causes a thing or what inheres in it may be seen as orthogonal to facts about what is sufficient for conceiving of that thing.There are similarly transparent reasons for seeing Spinoza’s claims about mind-body expression as incompatible with the claim that expression implies inherence. To begin with, the vocabulary of inherence is simply absent from these claims; Spinoza does not say that the mind is “in” the body, or that the mind and the body are “in” “one and the same thing”, whereas he does say that the mind expresses the body and that the mind and the body express one and the same thing. More significantly, however, Spinoza is uncontroversially committed to a further principle that seems clearly to preclude the possibility that expression implies inherence, namely: Yet this is not the picture of part/whole dependence one finds in Spinoza. He states in no uncertain terms that parts are prior to their wholes. Thus he writes in Letter 35: “For component parts must be prior in nature and knowledge to what is composed of them” (G IV.181.24–25/C II.27). The view is echoed in the Ethics, where Spinoza writes that it would be absurd to think that “the whole could both be and be conceived without its parts” (1p12d). So maintaining that expression implies causation leads us to expect the opposite conclusion about part/whole priority from the one Spinoza actually accepts. This again seems like a solid reason for rejecting (2).Spinoza here describes what’s sufficient to form a whole, which boils down to a kind of compositional unity. A whole is constituted to the extent that certain parts “agree” (consentiant) with one another. To be a whole of a certain nature just is to be composed of parts in a characteristically unified way. We can now cash out the difference between the notion of a compositional part and that of an inhering property using a device introduced above. We could say that a part is “situated” in its whole, just as a property is “situated” in that in which it inheres. But there is a crucial difference. Suppose that W is a whole, p one of its parts, and p’ just any portion of matter. Recall, next, that E stood for our “Extension context” and e for a mode of extension. We said that, for all E, ‘e is situated in E’ implies redness is situated in E. This is a way of representing Spinoza’s view that redness inheres in e, and both redness and e inhere in Extension. Spinoza would say, for example, that both e and redness “follow from” (sequituur), or are properties of, Extension, because both of the former are ways of being extended. By contrast, Spinoza would not similarly hold that, for all W, ‘p is situated in W’ implies p’ is situated in W. The entailment doesn’t hold because neither p nor p’ follow from the nature of W. The fact that p is situated in W is not a fact about p’s dependence on W, or about p’s way of being W, but rather about p’s contribution to the compositional unity of W.Spinoza famously declares: “For each thing there must be assigned a cause, or reason [causa seu ratio], as much for its existence as for its nonexistence” (1p11d2). This statement is typically read as meaning that there can be no account of a thing’s existing as the thing it is that appeals simply to the thing itself: there must be some independently specifiable feature, a causa seu ratio, that serves to make the thing’s characteristic existence comprehensible. The individuation of a thing depends on something other than the thing, some exogenous cause or reason, even if that cause or reason is something attributed to the thing as one of its features. It is, then, only such a cause or reason that can be sufficient for conceiving of the thing, only that which can supply its identity conditions along with the explanation of why it does rather than does not exist (or vice versa). On this reading, 1p11d2 is taken as the quintessential statement of what is widely regarded by Spinoza’s commentators as the categorical expression of Spinoza’s thoroughgoing rationalism.For Spinoza, as the sentence from 1p8s2 shows, definitions require us to appeal only to the thing defined, whose nature is antecedently assumed, not some independent feature without which we have no purchase on that nature. And as the passage from 3p4d indicates, a definition cites the efficient cause of a thing’s nature, not because that nature is nothing other than the effect of that cause, but because the cause is the one thing specifiable to which the thing’s nature is not opposed. No other cause could be invoked as accounting for a thing’s characteristic unity, since then we would not be referring to the conditions under which that thing’s nature could be posited. But there is something prior to the notion of what cause is sufficient to enable the positing of a thing’s nature, insofar as it excludes every cause that would “inappropriately” relate to the positing of it. And that is the nature of the thing itself.What, then, underlies Spinoza’s espousal of this notion of the characteristic unity of a thing, its basic nature? In 2p29d, he writes: “[A]ll things have been determined from the necessity of the divine nature, not only to exist, but to exist in a certain way, and to produce effects in a certain way.” For Spinoza, to exist as determinate is to express the necessity of God’s nature. The deeper motivation undergirding Spinoza’s metaphysics of expression would therefore appear to be that of revealing the character of metaphysical necessity, and of deriving everything that may be conceived from it. Just as the determinate natures of actually existing individuals are not settled by external factors or principles, so the nature of necessity itself is not the consequence of anything further. A careful look at 1p7 reveals that necessary existence does not accrue to substance in virtue of its essence:This conception of substance as necessary existence — existence which constitutes, rather than follows from, the essence of substance considered as embodying an independent reason for such existence — would therefore appear to be the conception of a brute necessity. At the foundation of Spinoza’s metaphysics is the view that the way a thing’s essence is expressed, though sufficient for conceiving of that thing, is not itself dependent on the way that thing is conceived. It rather dictates the way the thing must be conceived, if it is to be truly conceived at all. Hence, neither the necessary existence of a thing, nor the necessarily existing thing’s expression of its essence, issues from an independent reason. A parting comparison between Spinoza and Leibniz on this score should prove telling. For Leibniz, there can be no brute necessities, and that is because there is a “common notion” underlying both necessary and contingent truths. That common notion is precisely that, for every truth, one can give a reason for that truth. For necessary truths, that reason necessitates. Thus Leibniz writes:For Spinoza, by contrast, there is nothing in the notion ‘Adam who sins’ in virtue of which Adam exists. Adam who sins exists because he (the sinning Adam) is a way of being God, which is a way of existing necessarily. And this suggests a deeper answer to the question of what Spinoza means when he says that for each thing there must be assigned a reason or cause, either for its existence or for its nonexistence. For Spinoza, causality is simply ordered existence (1p16d&c1, 2p7&d&s). That order is a necessary order (1p29), and identifying the cause of a thing’s (non)existence amounts to nothing more or less than consulting the nature of necessity itself. For, Spinoza says, “a thing necessarily exists if there is no reason or cause which prevents it from existing” (G II.53.11–12). But we do not learn necessary truths from identifying the particular causes of particular things. We learn them through an adequate understanding of God’s nature (2p44c2d). In discovering a thing to follow from God’s nature as a matter of necessity, we thereby conceive of the reason or cause of its existence. Whatever does not follow from that nature, whatever is contrary to necessity, does not have a reason or cause for its existence. Spinoza’s stipulation that there may be a reason or cause that “prevents” a thing from existing necessarily is somewhat elliptical. Such a reason or cause does not prevent a thing’s existence in the face of necessity (since then its nonexistence would be contingent). Rather, any cause or reason for a thing’s necessarily not existing — barring sheer impossibility — is in fact no substantive cause or reason at all: the nonexistent thing does not exist because it is not a necessary thing, or is not such that its existence follows necessarily from the latter. There is no context outside of necessity itself for adjudicating whether a thing exists necessarily or not.Thus, to say that Adam is a way of existing necessarily (and that this in fact is all there is to the matter) is not to give an independent reason why Adam exists necessarily, whether located in the notion of ‘Adam’ or outside it. Adam’s way of existing consists in the way Adam’s nature is expressed, and it is only in virtue of his being expressed that there can be anything sufficient for conceiving of Adam — and of how Adam is an expression of God’s essence. For Spinoza, reason’s purpose emerges solely from, and is fulfilled exclusively by, its act of conceiving of Adam in the latter way. It is only in the fulfillment of this office that reason serves to make the nature of things intelligible. And hence Spinoza can separate out this impartial function of reason from its proverbial status as a mode of our thinking and a servant of our explanatory, which is to say proprietary, aims: “For it is one thing to inquire into the nature of things, and another to inquire into the modes by which things are perceived by us” (CM I.1/G I.235.34–35/CI.302).
