by Rory Brown
This is an edited reprint of an original version of this essay which originally appeared in AustLit in 2019.
The early modern period is usually thought to have begun with a revolution against the dominant Aristotelian paradigm at the turn of the 17th century.[i] This revolution was led by René Descartes (1596-1650) and Thomas Hobbes (1588-1679), whose rejections of the Aristotelian tradition ushered in a new era of philosophical thinking—the modern era.[ii] However, the revolutionary project arguably only manifested as a wholly separate system of thought in the work of Benedict Spinoza (1632-1677), who built upon the foundations laid by Descartes and Hobbes to create a radically different world view.[iii]
This essay seeks to demonstrate that Spinoza is the thinker who most radically departs from Aristotelianism. To this end, it offers a critical examination of Cartesian, Hobbesian and Spinozist metaphysics (particularly each of their epistemologies, ontologies, and methods of individuation). In the first section of this paper, I will examine Aristotelianism, the trends in scholastic thought that preceded Descartes, the Cartesian revolution, and the problems encountered by Cartesian metaphysics. In the second part, I will consider Hobbesian metaphysics, contrasting it with both scholastic and Cartesian thought. I will then turn to Spinozism, where it should become clear that whilst Descartes and Hobbes started a revolution, it is Spinoza who developed the most distinct metaphysical system.
II. Aristotelianism—An Unsteady Doctrine
Aristotle’s metaphysical system was the dominant paradigm at the turn of the 17th century. The precursor to the early moderns were the Scholastics, who operated almost entirely under Aristotelian metaphysics.[iv] Cartesianism is in many respects defined by its rejection of Aristotelian principles, however it is also clearly influenced by them.[v] It is therefore necessary to give an overview of Aristotelianism and the trends in scholastic thought that immediately preceded Descartes before discussing Cartesianism.
The two chief principles of Aristotelian metaphysics are form and matter, which inhere in all things that exist—and what exists are substances.[vi]This ontology is called universal hylomorphism; a substance is a thing’s nature, the subject of predication, and the fundamental explanation for why something is something per se.[vii] Under this ontology, substances, composed of matter and form, are required to have privation—the potential to change accidental forms—although, as Aristotle recognised, privation is in a sense merely incidental.[viii] Here, form is thought to be either substantial or accidental. The substantial form constitutes the very essence of a thing,[ix] whereas the accidental form refers to qualities such as colour, shape or size, which inhere in something but are not of something.[x] Matter is thought to exist only in a potential sense (as so-called prime matter), and does not exist prior to being informed however, once informed by the substantial form, operates as the principle of individuation.[xi] Aristotelian epistemology is also empiricist, in the sense that it holds knowledge of the world to be the product of the testimony of senses.[xii]
The Aristotelian account struggled with several problematic implications that commentators were never able to satisfactorily address.[xiii] For example, how can matter endure beneath changes in substantial forms if it is wholly potential before becoming informed?[xiv] Furthermore, if matter exists only by virtue of being substantially informed, how could it possibly serve as the basis for individuation between things with the same substantial form? It would necessarily have to have some aspect of its existence that is not contingent upon substantial form.[xv] Yet another question is whether there can be integral parts to a substance; for instance, does a heart have its own substantial form and, if so, are humans just an accidental compilation of substances, rather a substance in our own right?
The answers to questions such as this birthed a split in the Scholastics, with the Thomists on one side and the Scotists on the other.[xvi] The Thomists doubled down on the Aristotelian position that form and matter really were one and that matter lacked the capacity to exist without form—going so far as to maintain that God himself could not configure matter in such a way.[xvii]
On the other hand, the Scotists, led by Franciscans William of Ockham and John Duns Scotus (who carried the stylish moniker ‘The Subtle Doctor’), drew a series of different conclusions. Scotists reject the premise that matter is pure potentiality,[xviii] maintaining that matter has to be a substance if it is to persist through changes in substantial form at all. For instance, matter has to exist in its own right to support the claim that a corpse, with the substantial form of the cadaver, consists of the same matter as the animate body, with the substantial form of the soul.[xix] Scotists also reject that matter can serve as the principle of individuation, and, therefore, that the substantial form was required to do this.[xx] Scotus claimed that the integral parts of a thing need to have their own forms; accounting for the identity of composite things with ‘the form of the whole’.[xxi] Notably, Ockham rejected this as needlessly obscure, in accordance with his famous principle of parsimony. He instead pursued a nominalist method of individuation, which will be discussed later.[xxii]
At the turn of the 17th century, Scotism was the dominant interpretation of Aristotelianism,[xxiii] and in many ways, the Scotists’ conclusions seem to have paved the way for Descartes’ philosophy.[xxiv] This is because, at the time, matter was being elevated away from potentiality into something with its own existence. Form had begun to appear like something accidental, as matter no longer required it to exist. Furthermore, because the integral parts of something were increasingly thought of as all possessing their own substantial forms, it became much more difficult to justify the conclusion that composite bodies were actually individual things.[xxv] Moreover, centuries of interminable and voluminous debate over the same problems—identity over time, individuation, the existence of matter, composite bodies—made Aristotelianism appear inoperable. Anti-scholastic voices, some well known to Descartes, were already rising come the end of the 16th century.[xxvi] Even accounting for all this, the extent to which Descartes revolted was remarkable.
III. Descartes, the Revolutionary
Descartes began his revolt with an attack upon the Aristotelian epistemological foundations.[xxvii] Descartes was a rationalist, meaning he believed that humans were capable of using reason to discover metaphysical truths.[xxviii] He felt compelled to abandon empiricism in light of sceptical arguments, which he recognised as posing a serious threat to the credibility of his treasured physics.[xxix] Consequently, he adopted sceptical arguments in his Meditations to reach anti-sceptical conclusions, simultaneously warding off the sceptics and rebuffing Aristotelian empiricism.[xxx] The conclusions he reached in this work formed the basic elements he would later use to develop his ontology in Principles of Philosophy, wherein he would address issues such as God, the real distinction argument, and the existence of thinking things and matter.[xxxi]
The real distinction argument runs as follows. It is certain that God can create that of which we have a distinct understanding. Therefore, two things that can be clearly and distinctly conceived apart, can exist apart. That which can exist separate to something else is distinct from it. Therefore, if something can be clearly and distinctly conceived apart from something else, the two things are really distinct.
In the Principles, Descartes clearly lays out his ontological framework. He defines substance in a slightly different way to Aristotle; as that which does not depend upon anything else for its existence. For Descartes, only God can satisfy this property, and thus be substance, for he believes that the existence of all else is contingent on the existence of God.[xxxii] Because of this, he considers ‘secondary’ substances those which only rely upon God to exist; namely, body and mind. Descartes claims that we know these secondary substances exist because we can clearly and distinctly perceive their principal attributes, which are, according to him, extension and thought.[xxxiii] Descartes employs the real distinction argument as proof that they must be truly distinct substances. He labels the properties of extension (size, shape, position, and motion) and properties of thought (intellect, will, imagination, and sense perception) ‘modes’.[xxxiv] This ontological framework came to be known as dualism.
Individuation Within and Across Substances
Descartes never addresses the question of how to individuate souls. He simply assumes that they are pluralistically instantiated without explaining how (a conclusion later circumnavigated by Spinoza).[xxxv] By contrast, extended things are more ontologically complicated. Descartes sometimes claimed that corporeal substance refers to the one thing (a universal res extensa, an infinitely divisible plenum, lacking in empty space),[xxxvi] but at other times argued that there are real distinctions within matter; implying a plurality of corporeal substances all made of the same type of thing.[xxxvii] When making such arguments, Descartes used motion, which is a mode of extension, as the individuating criteria.[xxxviii] Another method of individuation for Descartes was the mind-body union. He believed that human beings were unified into individual things by virtue of the union of individual soul with body.[xxxix]
Appreciating the Cartesian Revolution
Descartes epistemologically and ontologically abandoned the Aristotelians. Rationalism (particularly when used in deploying sceptical arguments) is anathema to Aristotelian empiricism, and Cartesian dualism is clearly ontologically distinct from hylomorphism. The problems inherent in form-matter ontology were left behind, as matter completed the transformation initiated by the Scotists into a complete substance. Descartes employed a tactic reminiscent of Ockham’s Razor to formally relegate the traditional understanding of form to redundancy—he simply did not require substantial form, and so it was not made a feature of his metaphysics.[xl]
However, Descartes fell into a scholastic way of thinking about extended things when it came to a plurality of corporeal bodies. While his method for individuation remained distinct from that of the Aristotelians, his conclusions (e.g., that there are a plurality of instantiated physical things) were still quite similar to those embraced by Aristotelianism. As we will see, this became the subject of much criticism from other early modern philosophers.[xli]
IV. Setting a Trend: Early Modern Criticisms of Descartes
A brief overview of early modern critiques of Descartes reveals some of the problems Descartes encountered in accounting for his epistemology, ontological dualism, and method of individuation.
Spinoza was critical of Cartesian ontology.[xlii] His work highlights that Descartes’s treatment of extension and thought as substances was definitionally contradictory.[xliii] Like Hobbes, Spinoza pointed out, that Descartes could not use their inexplicability in terms of each other to conclude that they are different substances; on the contrary, one could only draw from this that we are unable to make inferences about one from the other.[xliv] Spinoza also criticised Descartes’s individuation by way of the mind-body union. In fact, Spinoza levelled a similar criticism at Descartes’ mind-body union as that famously offered by the Princess Elisabeth of Bohemia; that it is logically impossible for substances with nothing in common to causally interact.[xlv] Further to this, Spinoza criticised Descartes’ attempts to individuate bodies within the plenum; pointing out that if the res extensa really does consist of a full plenum, as Descartes believed, then there cannot be real distinctions within it, only modal ones—and modal distinctions cannot individuate substances.[xlvi] Spinoza’s criticisms are perhaps best understood in the context of his own metaphysics, which I will later explore.
Hobbes criticised Descartes directly, writing the Third Set of Objections to the Meditations. Like Spinoza, Hobbes challenged the validity of Descartes’ dualism, but unlike Spinoza, Hobbes did so from the position of a materialist.[xlvii] Hobbes’s materialism stemmed from his epistemological foundations which, unlike that of Spinoza and Descartes, were empiricist. Hobbesian thought presented more of a foundational rivalry to Cartesianism; one that requires more thorough exploration.
V. Hobbes, the Empiricist
Unlike Descartes, Hobbes was an empiricist; he believed that our knowledge of the world could be explained in terms of the mechanics of perception and signification alone. These beliefs underpinned his materialism, as well as his account of individuation.[xlviii] Hobbes believed that thought was the sensation induced by a chain of causally related movements, stemming from an external body.[xlix] According to Hobbesian epistemology, these sensations remain within us and we are able to manipulate them so as to imagine. Imagination forms the basis of our memory, as well as underpins our understanding; i.e., “the imagination that is raised in man by words”.[l]
A second strand of Hobbesian epistemology is his nominalism. Hobbes believed that names are arbitrary appellations used to assist with the recollection of memories—“we remember that vocal sounds of this kind sometimes evoked one thing in the mind”.[li] This led Hobbes to the controversial, but internally consistent, conclusion that our very partition of the world into kinds is an arbitrary exercise.[lii] This conformed with the belief held by Hobbes (and the other nominalists—most famously, William of Ockham), that only names are truly universal, which (because they are arbitrary) entailed the belief that there are no real universals.[liii]
The final strand that goes into Hobbes’s epistemology is his explanation of logic and reasoning as an exercise in computation; he argued in De Corpore that all reasoning can be understood as an exercise in the addition or subtraction of names to arrive at ‘truths’.[liv] It is here that his love of Euclidean geometry is most evident. These three strands provided Hobbes with what he considered to be a total account of human cognition.
Translating Epistemology into Ontology
Hobbes’s materialism was the product of his belief that the set of things of which we can have knowledge is limited by the ways in which we acquire knowledge.[lv] From Hobbes’s argument that all human knowledge and cognitive activity is retraceable to a chain of physical causation, it naturally follows that human knowledge and cognitive activity can only pertain to material things. Like Descartes with substantial forms, Hobbes simply does not require the immaterial in his ontology and, therefore, dismisses it;[lvi] thus, Hobbes’s ontology is purely materialist and monistic.[lvii]
Hobbes on Individuation
Because Hobbes is a nominalist, he has no need to give an account of individuation.[lviii] He nevertheless briefly addresses the issue, claiming that individuation occurs simply by virtue of a body’s existence in a place at a certain time.[lix] By his account, we can be certain that a thing exists because for us to perceive it requires it to have initiated a causal chain, which requires it to have motion, which means it is, therefore, an existing body. This account is somewhat unsatisfactory, for it arguably fails to account for something being the same even when its parts are replaced; for instance, when our perception of a body’s motion is unchanged, yet we are nonetheless confronted with a different set of matter over time.[lx] Furthermore, Hobbes’ account has trouble accounting for how we might be able to distinguish between bodies with identical relative motion; indeed, Hobbes struggled to provide satisfactory explanations for this.
Hobbesian work represents a different method of revolt against scholasticism to Descartes’s. Instead of abandoning the empiricism of the scholastics, Hobbes combined it with other scholastic ideas, such as nominalism, to construct a completely different metaphysics to the Aristotelians. Like Descartes, he abandoned the form-matter ontology but, unlike Descartes, he did so in favour of a materialist, substance monism. Nonetheless, as did Descartes and like the Scholastics, Hobbes maintained that there are individual bodies in the world (though he failed to provide a satisfactory account for their individuation).
VI. Spinoza, the Unyielding
Spinoza was deeply influenced by Descartes.[lxi] In many respects, Spinoza’s philosophy is simply strict adherence to Cartesian principles and the following of them, unflinchingly, to their proper conclusions.[lxii]
Spinoza, like Descartes, was a rationalist.[lxiii] He used reason in his quest to discover metaphysical truths, and his writing style is a reflection of this epistemological commitment. Like Hobbes, Spinoza was fascinated by the rationality of mathematics—which is why the Ethics, his major philosophical achievement, is presented as an exercise in Euclidian geometry.[lxiv] In his work, Spinoza provided a set of foundational definitions and axioms, then proceeded to rationally grant propositions which were verified with reference to those basic definitions. These propositions constituted his philosophy.
Part One of the Ethics concerns Spinoza’s metaphysics. The influence of Descartes is clear here—Spinoza inherits the language of substance, attribute and modes from Descartes. The noticeable terminological deviation is that Spinoza refuses to include matter and thought in the category of ‘substance’, as Descartes does; a refusal which can be seen as a criticism of Descartes’s decision to do so.[lxv] This has profound consequences. While each definition, axiom and proposition cannot be covered here, the particularly salient propositions are: the fifth (that no two substances can share the same attribute), the eleventh (that there is necessarily a substance with infinite attributes—which is, by virtue of an earlier definition, God), and the fourteenth (that God is the only substance).[lxvi]
The fifth proposition rests upon Spinoza’s shared assumption with Descartes that individuating a substance can be done only by reference to its attribute or modification (which is Spinoza’s fourth proposition). Spinoza highlighted that if something shares an attribute with another thing, then it cannot be individuated by virtue of attribute—obviously, since they share the attribute.[lxvii] Turning to modes, Spinoza argued that you cannot individuate a substance by mode,[lxviii] because modes are dependent upon substance, and, thus, the substance must be antecedent to it (since something cannot be individuated by virtue of what is necessarily subsequent to it). The refusal to individuate by mode is a challenge to Descartes’ arguments for multiple corporeal substances, but is arguably the proper application of Cartesian principles. Therefore, if something shares an attribute with something else, it cannot be a different substance to it, and hence the fifth proposition—that no two substances share the same attribute.
The eleventh proposition, that God, or a substance with infinite attributes, necessarily exists, is supported with three separate proofs—the reductio, the causal, and the potency arguments. Only the reductio argument will be discussed here. The reductio argument rests upon the seventh proposition; that existence belongs to the nature of substances, or that essence entails existence. The basis for this proposition is Spinoza’s view that if something exists, it must either be caused to exist by something else, or be self-causing. Spinoza rejected the possibility that one substance could be the cause of, or causally interact with, another substance,[lxix] in the third and sixth propositions. This constituted another departure from Descartes, who always struggled to justify his belief that mind and body could causally interact.[lxx] Spinoza moved from the rejection of inter-substance causal relationships to the corollary that the only cause of a substance can be itself.[lxxi] Therefore, if a substance exists, then it must be the cause of its own existence (or, in other words, the essence of a substance entails its own, self-caused existence). From this, it is relatively easy to prove God’s existence with the reductio: if God did not exist, then the essence of God would not entail existence, which is impossible. As it is impossible for God not to exist, God therefore exists.
With the fifth and eleventh propositions thus established, Spinoza was able to arrive at his metaphysical conclusion. This was done with the fourteenth proposition; that God is the only substance. Spinoza argues: if another substance existed, it would need to share an attribute with God (since God by definition possesses infinite attributes). If it shares an attribute with God, then it cannot be a different substance, by virtue of the fifth proposition. Consequently, there is only one substance, and that substance is God. This makes God synonymous with Nature; God is constitutive of the world. Spinoza was, therefore, a substance monist like Hobbes before him. At the same time, however, he was as far removed from materialism as was possible. Rather than arguing that there is one sense in which reality exists (e.g., the material), Spinoza concluded that there are an infinite number of ways in which reality exists, but that we can only comprehend two—through the attribute of extension and the attribute of thought.[lxxii]
As seen in the earlier section, Spinoza’s assumption that individuation of substance can be effected only by attribute or mode is fundamental to his metaphysics, for it leads him to rejectthe idea that there are multiple instantiations of either material or thinking things.[lxxiii] Instead, he posits that bodies can only be defined modally. Spinoza believed that ‘corporeal bodies’ are just modes of matter; while simple bodies could be explained through their relative motion and rest, complex bodies were definable through the relative motion and rest of the whole body, supplemented by the internalrelative motion and rest of its constitutive parts, and the whole’s ability to maintain its arrangement under change.[lxxiv] Spinoza renders the Cartesian soul naught but a mode of the attribute of thought, an idea in the mind of God.[lxxv] It is clear that Spinoza drew upon Cartesian ideas, but he repurposed them by applying them within his own ontological framework.[lxxvi] Spinoza also demonstrated a unique understanding of human individuality, arguing that humans have both mind and body, but that they are not unified in a Cartesian sense; rather, they are simply alternative perspectives from which one can consider the same, individual human.[lxxvii]
This essay has explored the metaphysics of Descartes, Hobbes and Spinoza, with a particular focus on their respective epistemologies, ontologies and methods of individuation. As we have seen, Descartes overthrew Aristotelian empiricism and ontology but was drawn to the Aristotelian conclusion that there were multiple instantiations of material things. Hobbes, on the other hand, shared the empiricism of the Aristotelians, but combined it with a host of other beliefs to construct a completely different ontology to Descartes—though he too returned to the conclusion that multiple bodies really existed. Conversely, Spinoza adopted the new epistemological framework from Descartes yet constructed a unique third ontological system that rivalled both Descartes’s and Hobbes’s. It is for this reason that I have argued that Spinoza was the first of the three thinkers to truly effect a radical departure from Aristotelianism.
Rory Brown is a student at the University of Queensland. His favourite areas in philosophy are ethics and politics, but he keeps returning to metaphysics and epistemology in the vain hope that maybe this time the most fundamental questions have been answered.
[i] Michael Ayers and Daniel Garber, “Introduction,” in The Cambridge History of Seventeenth-Century Philosophy, ed. Daniel Garber and Michael Ayers (Cambridge: Cambridge University Press, 2000), 2.
[ii] Roger Woolhouse, Descartes, Spinoza, Leibniz: The Concept of Substance in Seventeenth-Century Metaphysics (London, New York: Routledge, 1993), 2.
[iii] Genevieve Lloyd, Routledge philosophy guidebook to Spinoza and The Ethics (New York: Routledge, 1996), 9-11.
[iv] Roger Ariew and Marjorie Grene, “The Cartesian Destiny of Form and Matter,” Early Science and Medicine 2, no. 3 (1997): 300.
[v] Stephen Menn, Descartes and Augustine (Cambridge: Cambridge University Press, 1998), 4.
[vi] Robert Pasnau, “Form and Matter,” in The Cambridge History of Medieval Philosophy, ed. Robert Pasnau and Christina Van Dyke. (Cambridge, Cambridge University Press, 2014), 636.
[vii] Steven Nadler, Spinoza’s ‘Ethics’: An Introduction. (Cambridge: Cambridge University Press, 2006), 53.
[viii] Ariew and Grene, “The Cartesian Destiny of Form and Matter”, 301.
[ix] Pasnau, “Form and Matter”, 643.
[xi] Ariew and Grene, “The Cartesian Destiny of Form and Matter”, 301.
[xii] Menn, Descartes and Augustine, 5. (Menn, 1998, p. 5).
[xiii] Pasnau, “Form and Matter”, 635.
[xv] Ariew and Grene, “The Cartesian Destiny of Form and Matter”, 308.
[xvi] Ibid., 305.
[xvii] Ibid., 303.
[xviii] Pasnau, “Form and Matter”, 639.
[xix] Udo Thiel, “Individuation,” in The Cambridge History of Seventeenth-Century Philosophy, ed. Michael Garber and Daniel Ayer (Cambridge: Cambridge University Press, 2000), 213.
[xx] Ibid., 215.
[xxi] Pasnau, “Form and Matter”, 641.
[xxiii] Ariew and Grene, “The Cartesian Destiny of Form and Matter”, 310.
[xxvi] Ibid., 316.
[xxvii] Tom Sorrell, “Descartes, Hobbes and the Body of Natural Science,” The Monist 71, no. 4 (October 1988): 523.
[xxviii] Menn, Descartes and Augustine, 3.
[xxix] Sorrell, “Descartes, Hobbes and the Body of Natural Science”, 523.
[xxxi] René Descartes, The Philosophical Writings of Descartes, edited by J. Cottingham, R. Stoothoff, and D. Murdoch, vols. 1–2 (Cambridge: Cambridge University Press, 1985), 209-213.
[xxxii] Ibid., 210.
[xxxiii] Ibid., 210-212.
[xxxiv] Ibid., 24-27.
[xxxv] Thiel, “Individuation”, 223.
[xxxvi] Ibid., 224.
[xxxvii] Ibid., 225.
[xxxix] Alan Nelson, “Descartes’ dualism and its relation to Spinoza’s metaphysics,” in The Cambridge Companion to Descartes’ Meditations, ed. David Cunning (Cambridge: Cambridge University Press, 2000), 281.
[xl] Ariew and Grene, “The Cartesian Destiny of Form and Matter”, 318.
[xli] Nelson, “Descartes’ dualism and its relation to Spinoza’s metaphysics”, 285.
[xlii] Thiel, “Individuation”, 228.
[xliii] Nelson, “Descartes’ dualism and its relation to Spinoza’s metaphysics”, 287.
[xliv] Woolhouse. Descartes, Spinoza, Leibniz: The Concept of Substance in Seventeenth-Century Metaphysics, 26.
[xlv] Nelson, “Descartes’ dualism and its relation to Spinoza’s metaphysics”, 282.
[xlvi] Thiel, “Individuation”, 225.
[xlvii] Woolhouse. Descartes, Spinoza, Leibniz: The Concept of Substance in Seventeenth-Century Metaphysics, 21.
[xlviii] Stewart Duncan, “Hobbes: Metaphysics and Method,” (Dissertation, Rutgers, 2003), 35.
[xlix] Ibid., 35.
[l] Thomas Hobbes, Leviathan (Cambridge: Cambridge University Press, 1996), 2.10.
[li] Thomas Hobbes, De Corpore (Cambridge: Cambridge University Press, 1962), 2.9.
[lii] Stewart Duncan, “Thomas Hobbes,” in The Stanford Encyclopedia of Philosophy, ed. Edward N. Zalta, 2019.
[liii] Thiel, “Individuation”, 215-216.
[liv] Hobbes, De Corpore, 1.2.
[lv] Duncan, “Hobbes: Metaphysics and Method”, 11.
[lvi] Ibid., 15-18.
[lvii] Bernard Gert, “Hobbes on language, metaphysics and epistemology,” Hobbes Studies 14, no. 1 (2001): 50.
[lviii] Thiel, “Individuation”, 233.
[lx] Ibid., 235.
[lxi] Woolhouse. Descartes, Spinoza, Leibniz: The Concept of Substance in Seventeenth-Century Metaphysics, 3.
[lxii] Lloyd. Routledge philosophy guidebook to Spinoza and The Ethics, 14..
[lxiv] Woolhouse. Descartes, Spinoza, Leibniz: The Concept of Substance in Seventeenth-Century Metaphysics, 29.
[lxv] Nadler, Spinoza’s ‘Ethics’: An Introduction, 56.
[lxvi] Ibid., 60.
[lxvii] Benedictus de Spinoza, A Spinoza Reader: The Ethics and Other Works, ed. Edwin Curley (Princteon: Princeton University Press, 1994)l 4.
[lxviii] Ibid., 3.
[lxix] Ibid., 3, 6.
[lxx] Nelson, “Descartes’ dualism and its relation to Spinoza’s metaphysics,” 282.
[lxxi] Spinoza, A Spinoza Reader: The Ethics and Other Works, 6.
[lxxii] Woolhouse. Descartes, Spinoza, Leibniz: The Concept of Substance in Seventeenth-Century Metaphysics, 34.
[lxxiii] Ibid., 36.
[lxxiv] Thiel, “Individuation”, 229.
[lxxv] Woolhouse. Descartes, Spinoza, Leibniz: The Concept of Substance in Seventeenth-Century Metaphysics, 35.
[lxxvi] Lloyd. Routledge philosophy guidebook to Spinoza and The Ethics, 12.
[lxxvii] Thiel, “Individuation”, 229.
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