It’s not that Simple: An Objectivist Account of Spinoza on God’s Essence

2.1 The Argument from Silence

We have seen that a common objection against objectivism, the view that for Spinoza attributes are numerically distinct, is its alleged incompatibility with divine simplicity. An objectivist might argue that in Ethics, his main metaphysical work, Spinoza does not explicitly state the simplicity of God’s essence, indicating a shift from his earlier works, where he explicitly affirms God’s simplicity (CM II.5; KV I.2).^[15] Moreover, the objectivist can claim that this is consistent with the view that Spinoza sometimes changed positions concerning his view on the substance-attribute in his more mature writings. However, this argument is unconvincing, as one could easily turn this critique back on the objectivist. After all, the simplicity of God’s essence was widely accepted by Spinoza’s main philosophical influences, and so one might argue that more evidence is needed before concluding that Spinoza departs from the traditions that influenced him.^[16]

I believe that the objectivist can make their case stronger in two ways. First, she can point out that Spinoza develops a unique account of God’s essence, one that has no precedent in Scholastic, Jewish, or Cartesian philosophy – and one that is incompatible with divine simplicity. Note that Spinoza follows Descartes’s departure from Scholasticism in considering God a substance. But Spinoza also parts ways with Descartes when it comes to God’s essential attributes. For Descartes, “a substance may indeed be known through any attribute at all; but each substance has one principal property which constitutes its nature and essence, and to which all its other properties are referred.” In the case of God, the principal or essential attribute is Thought (PP I.54). On the other hand, Descartes acknowledges that God also has non-essential but necessary attributes or propria, including being “eternal, omniscient, omnipotent, the source of all goodness and truth, the creator of all things” (PP. I.22). Spinoza departs from Descartes in holding that Thought is not the only essential attribute of God.^[17] Instead, Spinoza makes the bold move of defining God as a substance that consists of an infinity of attributes (E1d6), including Extension and several attributes that are unknowable to human beings.^[18] For him, propria can only be incorrectly called ‘attributes’: “His ‘attributes’: it is better [to say] […] because these things are not God’s attributes. God is, indeed, not God without them, but he is not God through them, because they indicate nothing substantive, but are only like Adjectives, which require Substantives in order to be explained” (KV I.1). He believes that “through those propria we can know neither what the being to which these propria belong is, nor what attributes it has” (KV I.7.6).

Second, the objectivist might argue that it is not merely the absence of an explicit statement about God’s simplicity; Spinoza has two clear opportunities in Ethics where, if he does believe in God’s simplicity, he would have been expected to make it explicit: in his discussion of God’s propria and his account of divine indivisibility. Let us begin with God’s propria. Spinoza dedicates part I of the Ethics to explain God’s necessary properties. There, he posits that God necessary exists (E1p11), is unique (E1p14c1), is in himself (E1p15), acts from the necessity of his essence (E1p16), is the free cause of all things (E1p17c2), is the immanent cause of everything (E1p18), and has infinite power (E1p34). Simplicity, another proprium traditionally believed to belong to the divine being, is not included in an account that is as comprehensive as it is well-argued.

That this is not an accidental omission is further supported when we consider the opening passage of Part I’s Appendix:

With these [demonstrations] I have explained God’s nature and properties: that he exists necessarily; that he is unique; that he is and acts from the necessity alone of his nature; that (and how) he is the free cause of all things; that all things are in God and so depend on him that without him they can neither be nor be conceived; and finally, that all things have been predetermined by God, not from freedom of the will or absolute good pleasure, but from God’s absolute nature, or infinite power.

Spinoza begins this passage by making clear that the aim of Part I of the Ethics is primarily to explain God’s essence and properties (proprietates). That Spinoza refers here to what he has in his early works labelled God’s propria or necessary but non-essential properties is clear from the inventory of such properties that he provides: “that (and how) he is the free cause of all things; that all things are in God and so depend on him that without him they can neither be nor be conceived; and finally, that all things have been predetermined by God, not from freedom of the will or absolute good pleasure, but from God’s absolute nature, or infinite power.” For the purposes of my argument, the crucial point is that he does not mention God’s simplicity among these properties.

The other natural place where Spinoza could have mentioned God’s simplicity is in his argument for divine indivisibility in E1p13. There, Spinoza holds that the absolutely infinite substance, that is God, is indivisible because:

The parts into which it would be divided will either retain the nature of an absolutely infinite substance or they will not. If the first, then there will be a number of substances of the same nature, which (by E1p5) is absurd. But if the second is asserted, then (as above [NS: E1p12]), an absolutely infinite substance will be able to cease to be, which (by E1p11) is also absurd (E1p13).

Spinoza presents here a dilemma: (a) either the result of the division of the divine substance would produce a plurality of substances with God’s nature or (b) it would produce a plurality of substances with a nature different from God’s. Horn (a) is clearly unacceptable: Spinoza believes that there cannot be more than one substance with the same nature (E1p5). But horn (b) cannot be accepted either, since on this scenario the substance with all attributes would be destroyed. The objectivist can contend that the mere existence of this proposition supports their reading: since simplicity entails indivisibility, if Spinoza believes that God is simple, no such argument is required. Moreover, Spinoza does not consider the possibility of arguing for God’s essential indivisibility by alluding to God’s essential simplicity. Rather, he assumes the mereological complexity of God’s essence and then proceeds to show that the indivisibility of the components of this substance is impossible in practice.

One might object that Spinoza’s omission of God’s simplicity from these passages is merely intended to accommodate that God has modes and is thus irrelevant to the issue of the multiplicity of attributes.^[19] But to this objection it can be responded twofold. First, whereas God’s propria belong to God considered natura naturans (as substance or attributes), modes belong to God considered as natura naturata. Thus, the omission of simplicity from the list of God’s necessary but non-essential properties must relate to God understood as attributes or substance. Second, that Spinoza is dealing with attributes and not modes in E1p13 is attested by the fact that this division involves the attributes of the absolutely infinite substance constituting different substances. No mention is made here about the modes of that substance (that will have to wait until E1p16).

Therefore, by alluding to Spinoza’s distinct interpretation of divine essence and his omission of any explicit mention of simplicity in key passages of the Ethics where it might be anticipated, the objectivist can justifiably argue that Spinoza’s silence on the matter of divine simplicity indicates that he departs, in this respect, from the traditions that influenced him, and not that he agrees with them.

2.2 The Part-Priority Challenge

A more promising strategy against objectivism consists in arguing that, even if Spinoza does not explicitly endorse or reject God’s simplicity, he must still be committed to it for the sake of consistency.^[20] One way to do this is by pointing to the direction of the dependence relation holding between a whole and its parts. For Scholastic philosophers and also Descartes, whenever we deal with a composite or mereologically complex object, that object must depend ontologically upon its parts. This is so, because the part is prior in nature to the whole. For example, my arms, legs, and head are parts of my body. My body is composed of these parts, and hence it is posterior in nature and depends upon them for its existence. Let us put this principle more formally as follows:

Part-priority principle: if x partly composes y, then x is prior in nature to y.

Evidence that Spinoza accepts this principle can be found in the KV (I.2), where he says that if some thing is composed of different parts, “each part of it can be conceived and understood, and can exist, without the whole.” The part-priority principle also seems to appear in a letter where Spinoza posits that a being that necessarily exists “is simple, and not composed of parts. For in respect to their nature and our knowledge of them component parts would have to be prior to that which they compose. In the case of that which is eternal by its own nature, this cannot be so” (Ep.35). Thus, it can be argued that these passages constitute strong evidence for believing that Spinoza accepts the part-priority principle.^[21]

Now, Spinoza defines substance as “what is in itself and is conceived through itself” (E1d3). This definition is commonly read as the claim that a substance is ontologically and conceptually independent. That is, a substance does not depend on anything to exist, and the concept of a substance does not depend upon the concept of anything else. We can put this as follows:

Independence principle: x is a substance if and only if the existence and the concept of x does not depend upon the existence or the concept of anything else.

Note that if Spinoza believes that attributes are parts, then he cannot consistently maintain both the part-priority principle and the independence principle. By the former principle, the existence of God depends upon Thought and Extension. But then, it seems that God depends upon something else, and hence it is not, after all, ontologically independent, as posited by the latter principle. In what follows, I will refer to this apparent incompatibility as the part-priority challenge.

One way in which the objectivist can respond to the part-priority challenge is by showing that Spinoza rejects one of the two principles upon which it is founded. Since the independence principle is based in Spinoza’s definition of substance, rejecting it is not a viable option. A more promising strategy consists in rejecting the part-priority principle. The objectivist could try to do this by recalling that, in a famous letter to Oldenburg, Spinoza holds that parts in some way depend on their whole. There, he posits that the parts of the blood “are controlled by the overall nature of the blood and compelled to mutual adaptation as the overall nature of the blood requires” (Ep.32). In the same letter Spinoza says that each body is a part of the whole universe that must adapt to and be controlled by the whole. This passage seems to indicate that, after all, Spinoza does not accept the part-priority principle. And since this letter is later than KV, one could argue that this reflects Spinoza’s definitive position in this matter, and hence that he rejects the part-priority principle.

Unfortunately for the objectivist, this response is unsatisfactory. After all, Spinoza distinguishes between three kinds of composition:

From these three all composition arises. The first sort of composition is that which comes from two or more substances which have the same attribute (e. g., all composition which arises from two or more bodies) or which have different attributes (e. g., man). The second comes from the union of different modes. The third, finally, does not occur, but is only conceived by the reason as if it occurred, so that the thing may be the more easily understood. Whatever is not composed in these first two ways should be called simple (CM II.5).

Real composition is that involving substances as composing parts. Spinoza believes that an example of this is the Cartesian man, which on his reading would be the result of the composition involving an extended substance and a thinking substance. Modal composition is that holding between modes (e. g., the sum of modes of extension that compose my body). Finally, a composition of reason is not, strictly speaking, real composition: the intellect conceives as united things that are not united in reality. Note that the case of the corpuscles of the blood mentioned by Spinoza in Ep.32 seems to be restricted to the realm of the modes and is thus an instance of modal composition. On the other hand, Spinoza’s commitment to the part-priority principle in Ep.35 concerns the realm of substance. One can then contend that, at best, the objectivist has evidence that the part priority principle does not apply to modal composition, whereas what they really need is to show that it does not apply to real composition.^[22] In the following sections, I develop a response to the part-priority challenge on behalf of the objectivist that does not involve rejecting the part-priority principle or the independence principle.

3.1 Kinds of Parts

To see how the objectivist can successfully respond to the part-priority challenge, let us begin by considering a distinction briefly mentioned in this paper’s introduction. Medieval and some Early Modern philosophers, in contrast with contemporary philosophers, do not use ‘parthood’ univocally but distinguish between two kinds of parts in material substances: integral parts and metaphysical parts.^[23] Whereas the integral parts of a substance divide it with respect to quantity of measure, its metaphysical parts are not identifiable by empirical methods. To illustrate, consider the case of the particular Socrates, a material substance in Scholastic terms. Among the integral or quantitative parts of Socrates, we can include his arms and his head.^[24] On the other hand, the metaphysical parts of a material substance fall into three categories: (i) its essence and existence, (ii) its potency and act, and (iii) its essential parts – that is, its prime matter and substantial form(s).^[25] We can put it more formally as follows:

Metaphysical parts: If x and y are metaphysical parts of z, then either (i) x is the essence and y the existence of z (or the other way around), (ii) x is the act and y the potency of z (or the other way around), or (iii) x and y are each essential parts of z.^[26]

Among Socrates’s metaphysical parts we must then include his essence and existence, act and potency, and essential parts. Note that if the objectivist is to regard attributes such as Thought and Extension as parts of God, they cannot be metaphysical parts in the sense of (i) or (ii). This is so because for Spinoza essence and existence are numerically identical (E1p20) and in God everything is actual (E1p17s). Thus, if attributes are parts of God, they must be either integral parts or metaphysical parts in the sense of (iii).^[27]

Integral parts and metaphysical parts share the fact that they are proper parts; that is, they are, necessarily, many and cannot be numerically identical to their whole.^[28] To put the same point in a different way:

Proper parthood: if x is an integral or metaphysical part of z, then necessarily, there exists at least another part, y, that is also a part of z, and neither x nor y, independently of the other, is numerically identical to z.

The proper parthood principle applies to both integral and essential parts. However, Francisco Suárez, a philosopher whose strong influence on Descartes and Spinoza has been convincingly documented by prominent scholars, recognizes five relevant characteristics that distinguish one type of part from the other:^[29]

(i) It was widely accepted among Scholastics, including Suárez, that the essence of a thing explains what that thing is. But we have seen that, given the proper parthood principle, no metaphysical part is numerically identical to an essence. It follows that a metaphysical part is necessary but not sufficient for explaining what a thing is. To illustrate, consider the case of a human being. For Suárez this is a material substance with an essence constituted by two metaphysical parts: prime matter and form (rationality). Each of these parts is necessary to explain what a thing is: I cannot explain what a human being is without considering both her matter and form. But each metaphysical part, in isolation of the rest is not sufficient for explaining what a human being is – I cannot fully explain what a human being is just by alluding to his form. Conversely, for Suárez the integral parts of x do not belong to the essence of x, and hence do not explain what x is. Thus, the integral parts of a human being (her arms, legs, etc.) are neither necessary nor sufficient for explaining what that being is.^[30]

(ii) A metaphysical part comprises, encompasses, or spreads through the whole without being numerically identical to it (DM 5, VI.17).^[31] For example, each of the form and matter of a human being comprise the whole essence of that human being, but neither, independently of the other, is numerically identical to a human being.^[32] In contrast, an integral part of a substance does not comprise the whole substance. The arm and leg of a human being do not comprise the whole body of that human being. This helps to explain why the relation between essential parts and their whole is commonly characterized in terms of constitution, whereas the relation of integral parts is cashed out in terms of composition.^[33]

(iii) A metaphysical part is conceptually independent of other metaphysical parts of an essence but has no independent existence – they cannot exist one without the other.^[34] For example, Suárez holds that the constituents of the essence of a material substance “are really distinguished so that one is not the other and does not include the other intrinsically” (DM 15, XI.12). By holding that constituents are really distinct, Suárez is claiming that their distinction is independent of the intellect. Crucially, this does not mean that x and y are numerically distinct substances; one constituent of a substance, in isolation from the other, can at best be called an incomplete substance (substantia incompleta) or a part of a substance (DM 15, V.1, emphasis added). Thus, although the form and matter of a human being can be understood independently, only the result of their conjoining is a substance and thus they do not have independent existence.^[35] In contrast, an integral part of a substance is complete in itself, independently of the other integral parts of that substance. An arm of a human being does not require any other part of that human being for its completeness.

(iv) Metaphysical parts do not require anything external to account for their unity in one and the same essence. Suárez holds that although there is something added to reality by this union, this is not really distinct from the constituents or their sum, but only distinct as a “real mode” (realis modus) (DM 36, III.8). On this account, the union of essential parts is nothing over and above those parts. On the other hand, a collection of integral parts does require an external principle to account for their unity, or else they would be a mere aggregate.^[36] For example, a group of stones compose a pile of stones by mere aggregation. For them to constitute a unified integral whole, such as a house, an external cause - such as a construction worker - or a structure is necessary.

(v) At least one of the metaphysical parts of a material substance must be the cause and structure of the accidents of that substance. Specifically, the substantial form of a material substance, its active nature, is the cause of all his properties – such as having a flat nose or being white. Thus, Suárez holds that “the subordination of properties amongst themselves is an indication of substantial form” (DM 15, I.14). In contrast, integral parts cannot cause and structure the accidents of a substance. For example, the arm of a human being is not the cause of any of her properties.^[37]

3.2 Metaphysical Parts and the Part-Priority Challenge

We have seen that metaphysical parts have five relevant characteristics that distinguish them from integral parts. With this in mind, let us turn now to see how these characteristics can help the objectivist when it comes to addressing the part-priority challenge. For clarity, let us recall that this challenge arises from the apparent incompatibility between objectivism and Spinoza’s commitment to two principles:

Part-priority principle: if x is a part of y, then x is prior in nature to y.

Independence principle: x is a substance if and only if the existence and the concept of x does not depend upon the existence or the concept of anything else.

If attributes share the characteristics of metaphysical parts, the claim that the part-priority principle is inconsistent with objectivism is misleading. To illustrate why, consider the case of STE, a substance whose essence has two numerically distinct attributes as constituents: Thought and Extension. If these attributes are akin to metaphysical parts, STE is, obviously, an essentially complex substance. The relevant question is: does the existence of STE depend on the existence of its parts? Indeed, this seems to be the case, since one necessary characteristic of metaphysical parts is to be individually necessary and jointly sufficient for the whole that they constitute. Hence, it cannot be the case that STE exists if either Thought or Extension does not.^[38]

But here is the interesting bit: if Thought and Extension are understood as metaphysical parts, then it is also true that the existence of the whole depends upon the existence of its parts. Recall that another property of the metaphysical parts of a substance is incompleteness: only complete substances can exist. Hence, unlike a clock’s wheel, which can exist independently of that clock or of its other parts, Extension and Thought can only exist if God exists. Thus, if attributes are akin to metaphysical parts, attributes and substance depend on each other, and hence there is no priority in nature of part over the whole or of whole over part. Crucially, since Spinoza holds that the essence and existence of a substance are numerically identical, stating that a substance x depends on the metaphysical parts of its essence is equivalent to saying that x depends on itself. And this claim does not violate the independence principle. If the objectivist understands attributes as metaphysical parts, she can successfully avoid the part-priority challenge without rejecting the part-priority principle or the independence principle. But for this strategy to be cogent, the objectivist still needs to show that it is plausible to think that Spinoza understands attributes in this way. To be sure, one can legitimately contend that even if this is how Scholastics understand essences, Spinoza cannot understand attributes in this way, as he clearly favors a Cartesian framework of attributes and follows Descartes in rejecting hylomorphism. I turn to this issue in the following section.

4.1 Cartesian Attributes

Descartes famously posits that each substance has only one principal attribute which constitutes its essence (PP. I.53).^[39] For him, there are two kinds of substances: mind, a substance with Thought as its only essential attribute, and body, a substance with Extension as its sole essential attribute. In turn, each attribute of a substance is numerically identical to that substance. Thus, Thought is numerically identical to the thinking substance, and Extension is numerically identical to the extended substance. Since Descartes clearly rejects the hylomorphic account of essence constitution, it is tempting to think that Cartesian attributes are radically distinct to form and matter. However, Marleen Rozemond has recently argued, convincingly in my opinion, that this reading is only partially correct. Rozemond contends that, in effect, the notion of prime matter is dismissed by Descartes because once “it has been so deprived of all its forms and qualities that nothing remains that can be clearly understood.” But she posits that Cartesian attributes, including Extension, are direct descendants of substantial forms and more similar to them than is typically acknowledged:

since Descartes eliminates prime matter from the hylomorphic conception of corporeal substance, the result in Aristotelian terms is that a substance just consists in a substantial form. In Descartes’s own terms the result is that the substance just consists in a principal attribute […] whereas the notions of substantial form and principal attribute are different in many ways, the latter inherited some important features from the former, in particular, from a version of this notion found, for instance, in Aquinas and Suarez.^[40] (Rozemond, 2011, 11)

Rozemond identifies three characteristics that substantial forms share with Cartesian attributes: both are related to the essences of a substance in terms of constitution (they comprise the essences that they constitute), give a substance its being or actuality, and cause the properties of their substance.

One might worry that we are moving too quick here. After all, unlike forms, Cartesian attributes do not inform matter.^[41] Moreover, the only two kinds of attributes that Descartes admits, Thought and Extension, contrast with the great variety of substantial forms admitted by the Scholastics. Additionally, it is worth noting that Descartes is commonly read as holding that the distinction between substance and an essential or principal attribute is a conceptual distinction or distinction of reason.^[42] Hence, strictly speaking, Descartes cannot be thinking of attributes as forms. But note that Rozemond does not claim that for Descartes attributes are forms. Rather, she contends that, seen through an Aristotelian lens, a Cartesian substance would consist of a substantial form. The idea here seems to be that, given their remarkable similarities, when confronted with Cartesian attributes, a Scholastic philosopher would have regarded them as forms. And when it comes to addressing the part-priority challenge, this suffices for the objectivist’s purposes.

4.2 Spinozistic Attributes

We have seen that Cartesian attributes inherit some of the crucial characteristics of forms,

one of the two types of metaphysical parts that constitute essences in Scholastic thought. Descartes calls them ‘constituents’ but not ‘parts.’ Thus, if Spinoza is working within a Cartesian framework of attributes, we would expect him to ascribe the same characteristics to them.^[43]

(i) For Spinoza the attributes of a substance explain what it is. In E1p8s, he holds that “the true definition of each thing neither involves nor expresses anything except the nature of the thing defined.” Thus, he believes that the definition of x linguistically expresses the nature or essence of x – and, we have seen, for him, the attributes of a substance are its essence. Crucially, just as in the case of Suárez’s material substances, for Spinoza if a substance has more than one attribute, no attribute independently of the rest is sufficient for explaining that substance.^[44] To see why this is so, consider that in E2d2 Spinoza holds that “to the essence of any thing belongs that which, being given, the thing is [NS: also] necessarily posited and which, being taken away, the thing is necessarily [NS: also] taken away; or that without which the thing can neither be nor be conceived, and which can neither be nor be conceived without the thing.” This account of essences is commonly read as indicating that, for Spinoza, the essence of x implies the necessary and sufficient conditions for the existence of x. But then, one attribute of God, the absolutely infinite substance, cannot be sufficient for the existence of a being with an absolutely infinite essence.^[45] For example, Extension is necessary but not sufficient for the existence of a being consisting of all attributes. And since essences explain things, that attribute can at best partially explain the absolutely infinite substance.

(ii) Even if no attribute is sufficient for a substance with more than one attribute, each attribute comprises, encompasses, or spreads throughout its related substance. Spinoza posits that: “The thinking substance and the extended substance are one and the same substance, which is now comprehended (comprehenditur) under this attribute, now under that” (E2p7s). Comprehendo is usually translated into English as ‘comprehend’ but it can also mean ‘comprise.’ For example, this is true of the Latin, but also of Spanish and Portuguese, which, unlike English were languages spoken by Spinoza. His usage of this term clearly reflects this broader sense. Thus, in E2p8c he says that singular things are “comprehended” (comprehenduntur) in God’s attributes, and in E1p35d he posits that “whatever is in God’s power must (by E1p34) be so ‘comprehended’ (comprehend) by his essence that it necessarily follows from it, and therefore necessarily exists” (E1p35d).^[46]

(iii) In E1p12, Spinoza presents an argument for the indivisibility of substance that implies he views attributes as incomplete in the way metaphysical parts are. Spinoza holds that a substance cannot be divided because either the resulting parts of this division would be substances or else they will not. To illustrate, consider the case of a substance consisting of Thought and Extension: STE. If STE is divided, we would have either a substance consisting of Thought only – ST – and a substance with Extension as its only attribute – SE. But this is impossible, for a substance cannot be produced by another substance (E1p6) and each substance must be self-caused (E1p7). Thus, if we divide STE, Thought and Extension could not exist as substances. But neither can they lose the nature of substance, for then there would be no substance and a substance must necessarily exist (E1p7). Thus, the parts resulting from the division of a substance cannot exist independently of that substance, and the substance cannot exist independently of its parts. Moreover, this is consistent with Spinoza’s claim that “although two attributes may be conceived to be really distinct (i. e., one may be conceived without the aid of the other), we still cannot infer from that that they constitute two beings, or two different substances” (E1p10s).

(iv) A substance is nothing over and above its attributes.^[47] Spinoza holds that the essence of a substance is its existence. In turn, as we have seen, the essence of a substance is its attributes. This is consistent with his claim that God is a substance that consists of infinitely many attributes (E1d6 and E1p19). Spinoza does not posit anything in addition to the attributes to account for their unity. Rather, he says that it is of the nature of a substance that “all the attributes it has have always been in it together” (E1p10s).

(v) Attributes have causal and structuring power. Every mode that there is, whether infinite or finite, follows “from the absolute nature of some attribute of God-either immediately or by some mediating modification” (E1p23dem). For example, the existence of ideas “admits God as its cause insofar as he is a thinking thing” (E2p5), and the same is true for bodies with regards to Extension. Attributes structure modes, which follow from them with a certain order and connection (E2p7).^[48]

4.3 Objections and Replies

Attributes, as have seen, share five crucial characteristics of forms – one of the two kinds of metaphysical parts of essences acknowledged by Suárez. One might worry that despite all their similarities, Spinoza clearly rejects the Scholastic notion of substantial forms and dismisses them as “childish and frivolous” (Ep.13) and “clearly absurd” (CM 1.1). I believe that the objectivist can address this worry in two ways. First, they can note that this proposal does not claim that Spinoza identifies attributes with forms. Rather, following Rozemond’s account of Cartesian attributes outlined above, the suggestion is simply that Spinoza inherits from Descartes a notion of attribute that is more similar to metaphysical parts – and forms in particular – than what is commonly recognized.

Second, it must be noted that Spinoza does not say much on exactly why he rejects forms. The only reason he gives is that: “We have already pointed out that there is nothing in Nature but substances and their modes. So it is not to be expected here that we should say anything about substantial forms and real accidents, for these things, and others of the same kind, are clearly absurd” (CM 1.1). Thus, since the whole of nature can be explained in terms of substance (or attributes) and modes, forms are not necessary in Spinoza’s broadly Cartesian framework. One might add that Spinoza, just like Descartes, must reject forms because they can interact with other metaphysical parts (specifically, matter) and he is famously committed to what Della Rocca calls a ‘causal barrier’ between attributes. But as I have shown above, most of the characteristics and functions of forms are necessary in Spinoza’s account of attributes.

It can also be objected that Spinoza holds that God, the only substance, has an essence constituted by infinitely many attributes, and this at odds with the view that material substance is only constituted by one substantial form. However, the objectivist can respond by contending that, as Dominik Perler (2020, 146) has convincingly explained, the majority of medieval philosophers accepted that a material substance is constituted by a plurality of forms. Crucially, one of the reasons behind this reading is the need to explain the seemingly incompatible accidents of one and the same thing. Thus, it was posited that this incompatibility arises from the fact that each form is the cause of the accidents that follow from it. For example, the material substance Socrates has a rational form that explains some of its accidents, a material form that explains other accidents, and so on. Note that Spinoza’s absolutely infinite substance requires several causal principles. This is so because, as we have seen, for him the modes of each attribute follow from the nature of that attribute alone (E1p21 and E1p23). For example, Thought is active with respect to its own modes, as is Extension.

Another worry is that my reading seems to be at odds with Spinoza’s claim that “the human mind has an adequate knowledge of God’s eternal and infinite essence” (E2p47). Human beings can only know two attributes: Thought and Extension. But if each of the other infinitely many attributes is not numerically identical to God’s essence, how can the human mind have complete knowledge of that essence? Note that this is a challenge that affects every objectivist reading; regardless of how we understand the nature of attributes, if they are numerically distinct, then the human mind can only have adequately knowledge of God’s essence through the sum of all its attributes. Note that this challenge is also present for idealist and perspectivist readings. To see why this is so, consider first that Spinoza defines God as a substance consisting of infinite attributes. The difference between God and, say, a substance consisting of Thought, is that God has an infinitely many (or all) attributes. From this it follows that under idealism God’s essence consists of a plurality of concepts, under perspectivism it consists of a plurality of ways of presentation. But the human mind cannot know all of the concepts that constitute God’s essence, nor can it know all the ways in which that essence can present itself. Thus, the human mind cannot know God’s essence. This issue would be avoided if we adopt the reading of E1d6 as stating that God consists of all attributes, where ‘all attributes’ means exactly two: Thought and Extension. However, as I have mentioned before, there are convincing arguments for the view that, for Spinoza, God consists of infinitely many attributes. Thus, the adequate knowledge challenge seems to arise regardless of our preferred interpretation of Spinoza’s theory of attributes.^[49]

Finally, it can be objected that Spinoza does not use the term ‘part’ to refer to attributes. To be sure, the only kind of parthood explicitly endorsed by Spinoza in the Ethics is integral parthood which, in turn, is framed in terms of the relation of composition (see, e. g., E2p13). To this, the objectivist can respond by pointing out that this is a verbal dispute, and that the fact that Spinoza drops the language of parthood does not make less true that, in Scholastic terms, attributes are similar to metaphysical parts. He does, after all, use the relation of constitution to characterize the relation between attribute and essence. And, as we have seen, many-one essential constitution implies metaphysical parthood. Why, then, does Spinoza not explicitly refer to attributes as parts? One way of answering this question is by noting that returning to the language of parthood after adopting a Cartesian framework of attributes might have been misleading. Another possibility is that he does not want to further alienate Cartesian and Scholastic readers. But above all, the objectivist can respond to this question by noting that it puts an unfair burden upon her shoulders. After all, Spinoza’s definition of attribute as “what the intellect perceives of a substance as constituting its essence” (E1d4) is ambiguous and allows for several readings of exactly what he understands by attribute.^[50] And the objectivist can contend that it is more natural to assume that Spinoza’s understanding of the essential constituents of a substance blends together the long Scholastic tradition of metaphysical parthood – with which he was familiar – and a broadly Cartesian framework in which Thought and Extension are essential constituents than importing back contemporary categories to make sense of Spinoza’s account of attributes. In the next section, I show that by interpreting attributes through the lens of the Scholastic notion of metaphysical parthood, the objectivist can accommodate Spinoza’s definition of attribute.

5.1 E1d4

Any interpretation of Spinoza’s theory of attributes must be consistent with his definition of attribute as “what the intellect perceives of a substance as constituting its essence” (E1d4). Note that this definition involves two relations that need to be accommodated: a perception relation and a constitution relation. Let us begin with perception. An attribute is something that the intellect perceives of a substance. In a letter, Spinoza expands on this: “By substance I understand what is in itself and is conceived through itself, i. e., whose concept does not involve the concept of another thing. I understand the same by attribute, except that it is called attribute in relation to the intellect, which attributes such and such a definite nature to substance” (Ep.9). For Spinoza, then, an attribute must be attributed by the intellect to a substance. And for this to happen, an attribute must be distinguished by the intellect from that substance.^[51] We can put this more formally as follows:

Intellect: If x is an attribute of a substance S, the distinction between x and S involves the intellect.s

To illustrate, consider the case of a substance with an essence constituted solely by the attribute of Extension – call this SE. According to Spinoza, the distinction between SE and Extension involves the intellect.

Let us turn now to the constitution relation in E1d4. Although Spinoza does not explain what he understands by constitution, any objectivist interpretation of Spinoza’s theory of the attributes must accommodate the fact that this relation must track something outside the intellect. After all, the constitution relation between attribute and substance is perceived by the intellect, and for Spinoza “what is contained objectively in the intellect must necessarily be in nature” (E1p30).^[52] Let us put this second component formally as follows:

Constitution: x is an attribute of a substance S, x constitutes the essence of S – and the constitution of the essence of S by x obtains in reality.

The view that Spinoza models attributes on metaphysical parts has the advantage of naturally accommodating Spinoza’s use of both relations. Recall that essential parthood is characterized by Scholastics in terms of constitution. We also saw that the constitution of an essence implies that, although each metaphysical part of an essence must be numerically distinct, from this it does not follow that each attribute part has independent existence. Thus, on this reading the constitution of an essence obtains in reality, independently of the intellect. The objectivist can account for the perception relation in E1d4 by recalling that a substance is nothing over and above its essential parts, and the distinction between a substance and its essence involves the intellect. The distinction is relevant, however, for the essence of a thing explains what the thing is. And since the essence of a thing is numerically identical to the sum of its essential parts, the sum of the essential parts of a substance explains what that substance is. The objectivist can then cogently read Spinoza’s definition of attribute as the claim that an attribute is a metaphysical part of a substance that is grasped by the intellect in the process of explaining that substance.

5.2 What Kind of Objectivism?

The main aim of this paper was to show that, by adopting a reading of attributes as metaphysical parts, the objectivist can avoid the part-priority challenge.

My interpretation shows that only constitutive and structuralist objectivist are immune to the part-priority challenge. Recall that metaphysical parts avoid this challenge because one of their characteristics is to be, in isolation from the rest, incomplete, and hence cannot exist prior in nature to the whole. This is clearly the case of the constitutive interpretation of objectivism that I developed elsewhere (Borge forthcoming; 2022b). On my reading, Spinoza follows both the Scholastic tradition and the main Cartesian logicians of his time in accepting two views. First, that one and the same essence can have several numerically distinct constituents. When this is the case, that essence is numerically identical to the sum of its constituents. Second, that the distinction between a substance and the sum of its attributes is the distinction of between two ways of understanding one and the same thing: existence and essence. Thus, on my reading the sum of the attributes constituting the essence of a substance exists only as that substance. Consequently, if x and y constitute the essence of a substance S, then the division of x and y would imply the destruction of all S, x, and y.

But one does not need to be a constitutive objectivist to accept the incompleteness characteristic of attributes as metaphysical parts that allows the objectivist to avoids the part-priority challenge. This characteristic is also consistent with the outstanding structuralist kind of objectivism recently put forward by Don Garrett. Garrett posits that Spinoza adopts a strong ontological pluralism under which each attribute is a different manner of existence. He contends that Spinoza is familiar with ontological pluralism through his knowledge of the Cartesian distinction between two fundamental manners of existence that each thing can have – formal and objective – and holds that several passages in the Ethics indicate that, for Spinoza, this is the distinction that holds between Extension and Thought. But Garrett argues, convincingly in my opinion, that if Spinoza holds that ontological pluralism is true for Extension and Thought, it must also be true of every other attribute:

If Extension and Thought each constitute a different fundamental manner of existence, however, then it is natural to suppose that each of the infinitely many attributes that Spinoza posits does so as well […] Moreover, if each attribute constitutes a different manner of existence, then it is natural to infer, as Spinoza does, that greater total reality is correlated with a greater number of attributes (Garrett 2018, 276).

Under Garrett’s structuralist objectivism, necessarily there must be infinitely many manners of existence. It follows that the absence of only one manner of existence implies the absence of the rest.^[53]

On the other hand, the incompleteness characteristic that allows the objectivist to avoid the part-priority challenge is not available to the substantivalist and essentialist objectivism. Recall that under substantivalist objectivism each numerically distinct attribute is a numerically distinct one-attribute substance.^[54] On this reading, Thought is a substance, Extension is another substance, and so on. Since Spinoza believes that a substance is in itself (E1d3), and since for the substantivalist each attribute is numerically identical to a numerically distinct substance, on this reading each attribute must have independent existence. Essentialist objectivism is committed to a similar view. On this reading, each attribute is numerically identical to a numerically distinct essence.^[55] Thus, Thought is numerically identical to the essence of a substance, Extension is numerically identical to a numerically distinct essence, and so on. In turn, God is the substance with infinitely many one-attribute essences. The problem for the essentialist is that, for Spinoza, essence and existence are coextensive (E2d2). Thus, if each attribute is numerically identical to a numerically distinct essence, each can have independent existence.

5.3 Two Additional Advantages

I conclude by noting that the reading of attributes as metaphysical parts has two additional advantages for the objectivist. First, it allows the objectivist to avoid two problems related to attribute unity. The first challenge for the objectivist is to account for unity without resorting to something beyond the attributes.^[56] The reason for this is that for Spinoza God is omniscient and everything must be conceived or known through some attribute of God (E1p10s). Thus, if something transcending the attributes is responsible for their unity, then it would be unknowable even for God. Following Shein (2009) we can call this the ‘illusory knowledge challenge.’ The second challenge is to be able to differentiate between an aggregate and a genuine unity. For example, consider A. D. Smith’s claim (2014, 673 n37) that “according to ‘Platonists,’ both the null set and the proposition that justice is a virtue are necessary existents.” But there is no relevant sense in which the null set and this proposition are a unity. For simplicity, we can call this need to account for attribute unity while distinguishing real unity from a mere aggregate the ‘mere-aggregate challenge.’ Both the ‘illusory knowledge’ and ‘mere-aggregate’ challenges are avoided if we regard attributes as metaphysical parts. As we have seen, according to Suárez, metaphysical parts unite to form substances. Crucially, they do so in virtue of their nature – nothing in additional is needed or posited for their unity.

The second additional advantage has to do with the fact that my reading of attributes as metaphysical parts supports objectivist readings that remain consistent with Spinoza’s commitment to substance monism (e. g., E1p10s, E1p11, E1d14, E1p30dem, E2p7s), as substantivalism does, or to the view that a substance can only have one essence – a doctrine that he does not explicitly endorse and which goes against a long tradition where a thing can only have one essence. As far as I am aware, this view is not available to Spinoza via Suárez, Maimonides, or his Cartesian contemporaries – such as Descartes, Clauberg or Arnauld. Here I have argued that it is more natural to assume that Spinoza understands attributes as akin to metaphysical parts of the only substance. This reading is not as radical as it might seem at first sight. Rather, it involves accepting that Spinoza’s understanding of attributes blends together a long Scholastic tradition of metaphysical parthood – with which he was familiar – and a broadly Cartesian framework in which Thought and Extension are essential constituents.