In traditional philosophical terminology, this amounted to the theory of two totally distinct substances: mind and body. However, it should be noted that Descartes undermined the concept of substance and reduced it to something deliberately vague.
Therefore, philosophers who cling to the notion of substance as a reality will find substance dualism in Descartes; others, who focus on his attempts at explaining mental operations like perceptions and feelings in corporeal terms, will find him to be a proponent of physicalism. Adam, Charles and Paul Tannery, eds. Oeuvres de Descartes.
Paris: Vrin. Campanella, Tommaso. Compendio di filosofia della natura , eds. Germana Ernst and Paolo Ponzio, sect. Santarcangelo di Romagna: Rusconi. Cottingham, John G. The Philosophical Writings of Descartes , 3 vols. Cambridge: Cambridge University Press. Ryle, Gilbert. The Concept of Mind. Sepper, Denis L. Lawrence Nolan, New York: Cambridge University Press.
Ariew, Roger. Descartes among the Scholastics. Cottingham, John. John Cottingham, Hassing, Richard F. Lanham: Lexington Books. Markie, Peter. Ruler, Han van. North , eds. Lodi Nauta and Arjo Vanderjagt, Leiden: Brill. Specht, Rainer. Commercium mentis et corporis.
Stuttgart-Bad Cannstatt: Frommann-Holzboog. Voss, Stephen. Stephen Voss, New York: Oxford University Press. Ryle states: Body and mind are ordinarily harnessed together….
The Immaterial Nature of the Soul Descartes attempts to reconcile having an immaterial soul within a largely scientific and physicalist framework. On the Way to Substance Dualism Descartes entertained a notion of body, and of matter in general, that escapes the traditional terminology of substances.
In the sixth meditation, Descartes distinguishes material objects from mind and stresses: I have a clear and distinct idea of myself, in so far as I am simply a thinking, non-extended thing res cogitans, non extensa ; and on the other hand I have a distinct idea of body, in so far as this is simply an extended, non-thinking thing res extensa, non cogitans.
Reshaping the Concept of Substance As pointed out repeatedly, Descartes is working with and around a traditional philosophical terminology while trying to escape it. References Adam, Charles and Paul Tannery, eds. Further Reading Ariew, Roger. Adam and P. Tannery eds. Cottingham, R. Stoothoff, D. Murdoch, and A. Kenny trs. Previous: Introduction.
Causal isolation does not, however, entail causal impotence. An existing substance must have a cause in some sense, but as causally isolated its cause cannot lie in anything outside itself. Not only is a substance the cause of itself, but Spinoza later tells us that it is the immanent cause of everything that is in it E1P Last, Spinoza makes the case that substances are indivisible.
He argues in E1P that if substance were divisible, it would be divisible either into parts of the same nature or parts of a different nature. If the former, then there would be more than one substance of the same nature which is ruled out by E1P5. If the latter, then the substance could cease to exist which is ruled out by E1P7; consequently substance cannot be divided. From what has been said so far in the Ethics it would be reasonable to suppose that, for Spinoza, reality consists of the following substances: God, one extended substance, one thinking substance, and one substance for every further attribute, should there be any.
As it turns out, however, this is only partially right. It is true that Spinoza ultimately holds that God exists, that there is one extended substance, and one thinking substance. However, Spinoza denies that these are different substances. The one thinking substance is numerically identical to the one extended substance which is numerically identical to God. Put otherwise, there is only one substance, God, and that substance is both extended and thinking.
He argues as follows: God exists which was proven at E1P Given that God is defined as a being that possesses all the attributes E1d6 and that there is only one substance per attribute E1P5 , it follows that God is the only substance. So too, minds which Descartes had thought of as thinking substances are, according to Spinoza, modes of the attribute of thought. Like Descartes, Spinoza holds that the most real thing is God on which all other things depend.
However, there are no created substances. God as the one substance has all the attributes, and consequently is both an extended substance and a thinking one.
What Descartes had taken for created substances are actually modes of God. Nevertheless, Spinoza agrees with Descartes that the contents of reality come in two kinds—modes of extension and modes of thought, and there is a plurality of both. This account of the nature of substance yields a very different picture of the metaphysical structure of the world from Descartes and from common sense. First, created substances are the causal products of God.
However, substances are causally isolated, and so even if there were multiple substances, one could not be the causal product of the other. Spinoza agrees that being an ultimate subject is an essential part of being a substance; the problem is that finite bodies and minds are not ultimate subjects.
In general, Spinoza claims that what is distinctive of substances as ultimate subjects is that they can be individuated by attribute alone.
According to Spinoza there are only two kinds of mark by which entities might be individuated—by attribute and by mode. Substances as ultimate subjects cannot be individuated by mode, since subjects are metaphysically prior to modes. Two finite bodies, for example, are not individuated by attribute since they are both extended and so cannot be substances. Spinoza justifies this move defensively; at E1P10s Spinoza claims that nothing we know about the attributes entails that they must belong to different substances, and consequently there is nothing illegitimate about claiming that a substance may have more than one attribute.
Specifically, they claim he has a positive case that, in fact, a substance possessing anything less than all the attributes and hence, just one is impossible. In brief Lin asks us to suppose that Spinoza is wrong, and that it is possible for there to be a substance that has fewer than all of the attributes but at least one. Spinoza is a strong proponent of the Principle of Sufficient Reason see, for example, E1P8s2 according to which there is an explanation for every fact.
Given the PSR it follows that there is an explanation of why the substance in question fails to have all the attributes. Attributes are conceptually independent however, and consequently one cannot appeal to an existing attribute to explain the absence of another. For a different but closely related version of this argument see Della Rocca Here the focus is on ii. Spinoza was well aware of this argument and his official rejoinder is found in E1P15s.
For example, there is the part of extension which constitutes an individual human body, a part which constitutes the Atlantic Ocean, a part that constitutes Earth, etc. Despite his wording, Spinoza is not denying that extended substance has parts in every sense of the term. Rather, Spinoza is especially concerned to counter the idea that his extended substance is a composite substance, built out of parts which are themselves substances, and into which it might be divided or resolved.
Spinoza makes his case in two ways in E1P15s. First, Spinoza points us back to the arguments at E1P12 and 13 for the indivisibility of substance.
Second Spinoza offers a new argument that focuses specifically on extended substance, one that, interestingly, does not presuppose the prior apparatus of the Ethics. In general, he argues as follows. Consider an extended substance, say a wheel of cheese. If the parts of this wheel are themselves extended substances, then it is—at least in principle—possible for one or more of the parts to be annihilated without any consequence for the other parts.
The idea here is that because substances are independent subjects, the annihilation of one subject cannot have any consequence for the others. The problem with this is that the hole in the cheese is measurable—it has a diameter, a circumference, etc. In short, it is extended. However, we have supposed that the extended substance—the subject of the extension—in the middle was destroyed. For detailed discussions of this argument see Huenemann and Robinson In fact, Leibniz corresponded with Spinoza during the early s and briefly visited with Spinoza in Unlike Spinoza, Leibniz did not write a single authoritative account of his metaphysical system.
Not only that, but his metaphysical views changed in significant ways over his lifetime. Nevertheless, it is possible to identify a core account of the nature of substance that runs throughout his middle to later works from the Discourse on Metaphysics of through the Monadology of Second, Leibniz explicitly agrees with Descartes, Spinoza, and the tradition in maintaining that substances are the ultimate bearers of modes or properties. To be a unity for Leibniz is to be simple and without parts, and so the ultimate constituents of reality are not composite or aggregative beings.
They can neither begin nor end naturally, and consequently they last as long as the universe. Thus only composite entities are naturally generable or destructible. To say that a substance is active is to say not only that it is causally efficacious, but that it is the ultimate created source of its own actions. Substances, in some sense, have their entire history written into their very nature. The history of each substance unfolds successively, each state causally following from the previous state according to laws.
Like Spinoza, Leibniz holds both that substances are causally efficacious, and that their efficacy does not extend to other substances. In other words, although there is intra-substantial causation insofar as substances cause their own states , there is no inter-substantial causation. Leibniz offers a number of different arguments for this claim. On some occasions he argues that causal isolation follows from the nature of substance. Elsewhere he argues that inter-substantial causation is itself impossible, claiming that the only way that one substance might cause another is through the actual transfer of accidents or properties.
Although Leibniz agrees with Descartes that God is an infinite substance which created and conserves the finite world, he disagrees about the fundamental constituents of this world. For Descartes there are fundamentally two kinds of finite substance—thinking substances or minds and extended substances or bodies. Leibniz disagrees; according to Leibniz and this is especially clear in the later works there are no extended substances.
Nothing extended can be a substance since nothing that is extended is a unity. To be extended is to be actually divided into parts, according to Leibniz, and consequently to be an aggregate. Rather, there is a whole spectrum of simple substances of which human minds are a particularly sophisticated example. God exists and is responsible for creating and continually conserving everything else. The ultimate constituents of reality are monads which are indivisible and unextended minds or mind-like substances.
This article will take up three in particular. Our everyday experience is of extended objects causally interacting, but for Leibniz at the fundamental level there is no inter-substantial causation and there are no extended substances.
How, then, is the world of our experience related to the world as it really is? Let us begin with the apparent causal relations between things. Recall that, for Leibniz, monads are active and spontaneous. Leibniz writes in A New System of Nature ,. God originally created the soul and any other real unity in such a way that everything must arise for it from its own depths…yet with a perfect conformity relative to external things…There will be a perfect agreement among all these substances, producing the same effect that would be noticed if they communicated through the transmission of species or qualities, as the common philosophers imagine they do.
How does our experience of an extended world of bodies arise? He writes in an oft-cited passage to DeVolder:. In other texts however Leibniz claims that bodies result from, or are founded in, aggregates of monads, and this suggests that bodies are something over and above the mere perceptions of monads.
In general, scholars have offered interpretations that attempt to accommodate both sets of texts and which see bodies as being aggregates of monads that are perceived as being extended.
There is a great deal of debate, however, about how such aggregates might ultimately be related to bodies and their perception for one account see Rutherford b: Leibniz thinks composite beings are excluded as possible substances on a number of grounds.
First, no composite is or can be a unity, since according to Leibniz there is no way that two or more entities might be united into a single one. He famously illustrates this claim by appealing to two diamonds. He writes in his Letters to Arnauld :.
One could impose the same collective name for the two…although they are far part from one another; but one would not say that these two diamonds constitute a substance…Even if they were brought nearer together and made to touch, they would not be substantially united to any greater extent… contact, common motion, and participation in a common plan have no effect on substantial unity.
In general, there is no relation that two or more entities might be brought into that would unify them into a single being. A second and perhaps even deeper problem with composites is that according to Leibniz they cannot be ultimate subjects.
For example, what constitutes the essence of an army is only a mode of the men who compose it. This leaves us with a question, however: Why does Leibniz think that aggregates are mere modes or states of their parts?
In his influential book R. That is, everything that is true of an aggregate can be expressed by attributing various modes to the parts, all without appealing to the aggregate itself. Although Spinoza and Leibniz offer very different pictures of the structure of reality, their respective accounts of substance overlap in important ways: Both agree that to be a substance is to be at least i an ultimate subject, ii causally isolated but causally efficacious, and iii indivisible. Indeed, a number of scholars have suggested that Leibniz briefly adopted or was at least tempted by a Spinozistic metaphysics early in his philosophical career see, for example, the discussion in Adams He would be right if there were no monads.
Although they differ in a number of important ways, perhaps the most prominent difference between the metaphysics of Spinoza and Leibniz is that Leibniz holds that reality is split into two: God and creation.
God is a substance and He produces finite substances—created monads. Whatever property that, all by itself, allows you to clearly conceive of the substance, then, must necessarily be the essence of that substance. The full proof that thought is the essence of mind, and extension of body, will come in the next section. A mode, on the other hand, is much less intimately connected to a substance.
A substance could exist without any particular one of its modes though it could not exist without any modes at all. For instance, a substance could exist without being square, but it cannot exist without being shaped. A mode is actually just a particular way of being the principal attribute. A principal attribute is something determinable, i.
SparkTeach Teacher's Handbook. Important Quotes Explained. Summary I. Page 1 Page 2. Summary The discussion of substance and its properties is much more complex than the discussion of eternal truths, but once all the terms are sorted out it is not that difficult to grasp. Previous section I.
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