Spinoza, Descartes, and concept Dualism


In this paper, I will show that Spinoza made improvements to Descartes’ concept dualism in three significant ways, but fell short when he continued to embrace the distinct nature of the attributes of mind and body. He improved Descartes’ ontological argument, solved the problem of mind – body interaction, and dispelled the notion of an anthropomorphized deity. I will show that mind and body are in fact the same thing, thus improving the notion that God or nature is the primary cause.

Since Spinoza essentially stands on Descartes’ shoulders, I will first outline Descartes’ metaphysics, along with some pertinent outside references. Descartes wants to be certain that he has not adopted some tradition that may be at fault to build a certain foundation of what really exists. He writes, “I should withhold my assent no less carefully from opinions that are not completely certain and indubitable than I would from those that are patently false” (Ariew 41). He therefore adopts a methodology of doubt in a dialectic of skepticism, going back and forth as his own antagonist. He doubts the untrustworthy evidence of his senses much like Montaigne had done before him, embracing his own brand of Greek Pyrrhonian skepticism like Sextus Empiricus before that. Empiricus wrote: “…and of course the clear and certain truth no man has seen nor will there be anyone who knows about the gods and what I say about all things” (Cohen 27). The state where judgments are withheld from anything that is not evident has its own term in Greek, epoché, and so Descartes has strong foundations for his method. As Descartes writes, “There are no definitive signs as to distinguish being awake from being asleep” (Ariew 41). He probably was not aware of the kinship of his thought with Phyrro’s Chinese contemporary Zhuangzi, who dreamt he was a butterfly and upon waking did not “know if Zhuangzi dreamt being a butterfly or a butterfly is dreaming being Zhuangzi—though there must be a difference” (Hansen).

Descartes resolves from this confused state that even if his senses fool him about everything, it is an undeniable certainty that he is thinking. Even if there is some supernatural deceiver, “he will never bring it about that I am nothing so long as I shall think that I am something” (Ariew 43). It would be logically inconsistent to doubt that one was doubting, and doubting is a type of thinking, and so the awareness of being is established as a fundamental truth of existence. He has established thought or mind as one necessary type of substance. He then goes on to consider himself a “thing that thinks,” and a thing that perceives “body” to be “filling up space in such a way as to exclude any other body from it” which can be moved and sensed (Ariew 44). This, now, is another distinct type of substance, since thought does not seem to take up space, and bodies undergo changes whereas the concept of “2 + 3 = 5” remains consistent. He has now established the two primary, irreducible substances: mind and body.

Descartes next posits “as a general rule that everything I very clearly and distinctly perceive is true,” which allows him to not only trust ideas but also the existence of bodies (Ariew 47). He then determines that he has a clear & distinct perception of the existence of God. He writes, “[I]t would be impossible for me to exist, being of such a nature as I am (namely, having in me the idea of God), unless God did in fact exist” (Ariew 54). This alludes to what is called the cosmological argument, which maintains that God is the principle cause of existence. The other argument for God’s existence is called the ontological argument, which asserts that existence is a necessary attribute of a perfect being. Descartes explains thus: “My understanding that it belongs to God’s nature that he always exists is no less clear and distinct than is the case when I prove of any shape or number that some property belongs to its nature” (Ariew 59). He argues that existence cannot be removed from the clear idea of God, but also argues that it is God that provides the consistency required to maintain clear & distinct perceptions. There is a circularity to this argument that is irksome, but I think it will soon be resolved.

Leaving that aside for the moment, let’s go back to the dual substances of mind and body. Descartes proposes that bodies are divisible, whereas thoughts are not, and this therefore demonstrates that the two substances are distinct and do not affect one another. Mind to Descartes is the true essence of being, and can be understood to include the idea of soul. The mind being non-physical, and bodies being physical, each does not have a clear causal means for one to affect the other. When this was pointed out to Descartes in a letter from Elizabeth, Princess of Bohemia, who asked how an immaterial mind could cause a material body to move, he suggested that there was a third substance that was the union of body and mind with its own attributes. This response, however, erodes the necessary duality of his previous construct and is not satisfying, although it is more accurate than Descartes might like to believe.

I find Spinoza’s pantheistic construct to be a more satisfying concept constructed from Descartes’ components. He begins by defining something that is self-caused as having existence as a necessary attribute, “whose nature can be conceived only as existing” (Ariew 144). This appears to allude to the cosmological argument in that it suggests a first cause. He defines a substance as the most basic type of thing that does not require the conception of some other thing. Attributes arise from the perception of substances, with the principal attribute being the main inseparable perception of that substance. Modes or affections are secondary, tertiary, and otherwise less primary attributes that arise in the intellect from a substance or through its attributes. Spinoza defines God as an “absolutely infinite being, that is, substance consisting of infinite attributes,” with “absolute” signifying a broader form of infinity than might otherwise be assumed (Ariew 144). He distinguishes this infinity from an “infinity in its kind,” which could be construed as having less than infinite attributes (Ariew 144).

In order to make the argument that everything is one kind of substance, Spinoza begins by proposing that there is no substance that does not have attributes (Ariew 145). Since an attribute is a perception of a substance, and the essence of the substance that which is being perceived by definition, it would seem evident that this is so. If it cannot be perceived, then it is not a substance, and if it is not a substance, it cannot have attributes. They are bound up one with the other. Then, he proposes that there cannot be two substances that have the same attributes (Ariew 145). If something has the same attribute as another thing, then they are the same substance. Third, there is a substance that has every attribute, and that substance is “God or nature,” expressed in Latin as Deus sive Natura (Ariew 147). Therefore, since anything which shares the same attributes is the same substance, and all attributes are inherent in God or nature, then God or nature is the single substance that exists (Ariew 149). In another way of expressing it, God or nature IS existence itself. Although the attributes of mind and body are the ones we can identify, there are infinite attributes of God or nature that we cannot comprehend.

Spinoza diverges from Descartes in that he finds thought and extension (also known as mind and body) not to be distinct substances made possible by a separate God but instead distinct attributes of the single substance, God or nature. This allows him to get around the problems that Descartes had with the interaction of these as two distinct substances, one material and the other non-material. God or nature is the one infinite substance that has both infinite and finite modes, and it does not require the concept of any other substance to exist, because it is existence. It is self-caused, but since it is eternal, to label it as “caused” is a little off since it implies there was a time before God or nature existed.

Spinoza also improves the ontological argument in an interesting way. The presumption of the existence of God from the definition of God as perfect, as Descartes proposes, begs the question. When God is defined as existence itself, then the logic becomes more difficult to refute. If my awareness of my existence is proof that I exist, then the recognition that anything exists proves that God or nature, understood to be existence itself, exists. Just as it is not possible for Descartes to doubt that he is doubting, with doubting being a mode of thought that in turn proved his individual existence, it is necessarily the case that things exist. As Descartes himself writes in the Second replies, “Existence is contained in the idea or concept of every single thing, since we cannot conceive of anything except as existing” (Nolan). Spinoza asserts that “existence belongs to the nature of substance,” and that since no two substances can have the same attribute, and can only be limited by a substance of the same nature, substance must be infinite (Ariew 146). The proposition that everything exists because it has always eternally existed at its most basic form has simplicity to recommend it. I think of this as saying that God or nature is why things exist as opposed to not existing. Spinoza’s view is reminiscent of earlier Greek monists such as Anaximander, who we hear of through Aristotle’s Physics:

Of those who declared that the arkhé (first cause) is one, moving and apeiron (infinite), Anaximander . . . said that the infinite was the first cause and element of things that are… He says that the first cause is neither water nor any of the other things called elements, but some other nature which is infinite, out of which come to be all the heavens and the worlds in them (Cohen 13).

Part of Descartes’ difficulty comes from considering God to be an agent separate from existence rather than existence itself. This pantheistic view was considered heretic since it removes the agency of an anthropomorphized creator God, which was a feature of cosmology preferred by the hierarchical power structure. Spinoza considered his explanation to be an improvement from an agent God, as do I.  As human beings, we have a strong desire to project something of our experience among the affections of existence onto the irreducible elements of existence itself, but this is an error. Our “cause” in the bulky, mundane world may be a father and mother, but the ultimate cause is a different kind of material, and repeated insistence on referring to it as having human-like characteristics directs our thinking along comfortable but erroneous paths.

Spinoza writes that since the principle substance is God or nature, and that all things that exist are modes of the basic attributes of God or nature, when we think of things, we are actually exercising a capacity of God or nature that is within us. We think we have freedom to cause things to happen, but this is only because we are ignorant of all of the causes that have led us to the point of our own thinking and being. In fact, everything is God or nature, since everything is made up of just one substance, and so all actions and objects are a result of God or nature, and God or nature is a result of itself. This also answers the question of whether we can have innate ideas, since whatever is in us naturally is there because it is the way it has to be. In Spinoza’s view, there is still no causal relationship between mind and body. Because they are things that have nothing in common, they cannot limit one another. He thinks they are both caused in parallel by the single substance which is God or nature. This results in everything being caused by God or nature in every moment.

My proposition is that since mind and body have in common that they are both attributes of the single God or nature substance, then they are in fact the same thing. Spinoza describes these divine single substance attributes as natura naturata, which is the passive sense of nature, and natura naturans, which is the active sense. Extension is the passive attribute of God or nature, and Thought is the active attribute. I suppose I would say that the only attributes that can be thought of through nothing but themselves and yet still share an attribute are these two principle attributes, with all other affections or modes adhering to most the other definitions, axioms, and propositions as already described. Aristotle also contended in his Physics that physical objects were a compound of matter and form (which could be considered as a blend of body and mind) in what is known as hylomorphism, and though it is worthy of mention it is currently outside of my confident understanding (Ainsworth).

It is as if at the utmost layer of perception that define the active and the passive, the two become indistinguishable, which tends to confound logic and the senses because it is dimensionally beyond that realm. In fact, logic and the senses being mind and body respectively, it makes sense that they would be confounded at this dimension. A Taoist would call the passive principle of nature “Yin” and the active principle “Yang.” In Taoism, each of these components is depicted as having a small amount of the other incorporated within it, to represent that those things that we perceive as being as radically different as imaginable are in fact one and the same, and necessary components of each other. Consider the parallel with the words of Lao-tzu:

“There was something formless and perfect before the universe was born.

It is serene. Empty.  Solitary. Unchanging.

Infinite. Eternally present. It is the mother of the universe.

For lack of a better name, I call it the Tao.

It flows through all things, inside and outside, and returns to the origin of all things.

The Tao is great. The universe is great. Earth is great. Man is great.

These are the four great powers.

Man follows the earth.  Earth follows the universe. The universe follows the Tao.

The Tao follows only itself.” (Lao-tzu 25)

Notice how the single infinite substance for Lao-tzu is called Tao, which like God or nature for Spinoza pervades all things, and all things (attributes) are caused by it and part of it. Also notice the same desire to identify the principle cause as a parent, in this case “mother.”

If we accept for now that body and mind are the same thing and distinct at the same time, we find other interesting parallels. Let’s look at the concept of parallels itself. To be parallel lines which never meet requires two dimensions, but at the level of the infinite singularity, two dimensions are not appropriate. How could we understand parallel lines at one dimension? The question seems absurd. It is like the novella Flatland by E. A Abbott, in which a two dimensional being (a square) interacts with a sphere intersecting his planar universe and must try to expand his understanding of the basic assumptions of the universe to put the encounter in context (Abbott). It is the same problem that Zeno encounters when trying to describe the dimension of length using dimensionless points of location. It is like this in contemplating the attributes of the single substance—the distinction counterintuitively vanishes.

Physics has given us the eloquent equation E = mc2, in which energy is the active component and mass or body is the passive component of what exists, and they are equal. It gives us another basic attribute that seems to belong to both mind and body, and that is time. Time is an essential component of existence that seems to have been underappreciated by both Descartes and Spinoza. Certainly, it is a component of the change that distinguishes bodies from thought for Descartes. If mind is indeed the active principle of existence, it would seem that activity requires time to accomplish anything, as well. In Einstein’s famous equation, time is linked to the one substance that moves the fastest—light. The “seeing” that is used as a metaphor for knowledge is not possible without it. While light has an outer limit, we now know that time is an aspect of space and can change with the perspective of an observer at motion. In quantum physics there is an experiment referred to as quantum entanglement, where influence on one particle affects another particle at a distance:

“It thus appears that one particle of an entangled pair “knows” what measurement has been performed on the other, and with what outcome, even though there is no known means for such information to be communicated between the particles, which at the time of measurement may be separated by arbitrarily large distances” (Wikipedia).

This is what Einstein called “spooky action at a distance,” and demonstrates that there is a real mechanism for causation that cannot be adequately explained by mundane terms (Wikipedia).  It is good to note that in this case, the things that are linked causally are most certainly of the same type of substance. While cause is normally understood in a bulky Newtonian universe, where even light is required to travel through space at a limited speed, in this new quantum universe change and cause can occur instantaneously over time and space. Apparently there is even evidence of “Evolutionarily Designed Quantum Information Processing of Coherent States in Prokaryotic and Eukaryotic DNA Systems” (Moran 1). I am not sure that this paper is the proper milieu to explore this, but it seems worthy of further contemplation.

When Spinoza redefined God or nature as existence itself, he made the proof of God self-evident. By insisting on a continued separation of body and mind, however, he projected the same human need for comfortable paternal ideas onto his cosmology, something that he had specifically avoided up to that point. By considering mind and body to in fact be the same and distinct at the same time, we recoil at the idea because our ability to comprehend the universe is necessarily caught up in the tension between these attributes rather than the resolution of them. That resolution will eventually come to us all in our paradoxically impossible non-existence. I arose this morning to an article about the philosopher Daniel Dennett, who says that there’s nothing special about intuition: “Intuition is simply knowing something without knowing how you got there”(Buckley). And so Spinoza’s highest form of knowledge is exposed to itself be a form of ignorance.


Matthew Ebert
PHIL 213 – 1001
Dr. Fisette
4 April 2017


Works Cited

Abbott, Edwin A., 1838-1926, and Ian Stewart 1945. The Annotated Flatland: A Romance of Many Dimensions. Perseus, Cambridge, Mass, 2002. Print

Ainsworth, Thomas. Form vs. Matter. Stanford Encyclopedia of Philosophy. 8 Feb 2016. Web. https://plato.stanford.edu/entries/form-matter/ Accessed 3 April 2017.

Ariew, Roger, and Eric Watkins 1964. Modern Philosophy: An Anthology of Primary Sources. Hackett Pub. Co, Indianapolis, Ind, 2009. Print.

Buckley, Anna. Is consciousness just an illusion? BBC Science Radio Unit, BBC News. 4 April 2017. http://www.bbc.com/news/science-environment-39482345 Accessed 4 April 2017.

Hansen, Chad. Zhuangzi. Stanford Encyclopedia of Philosophy. 17 December 2014. Web. https://plato.stanford.edu/entries/zhuangzi/ Accessed 3 April 2017.

Lao-tzu, and Stephen Mitchell 1943. Tao Te Ching: A New English Version. Harper & Row, New York, 1988. Print.

Moran, Annalynn M. Quantum Entanglement. Nova Science Publishers, Inc, 2011. Physics Research and Technology. EBSCOhost, unr.idm.oclc.org/login?url=http://search.ebscohost.com/login.aspx?direct=true&db=e025xna&AN=542022&site=ehost-live&scope=site.

Nolan, Lawrence. Descartes’ Ontological Argument. Stanford Encyclopedia of Philosophy. 18 Jun 2001; revised 2 Sep 2015. Web.   https://plato.stanford.edu/entries/descartes-ontological/ Accessed 3 April 2017.

Wikipedia. Quantum Entanglement. https://en.wikipedia.org/wiki/Quantum_entanglement#Non-locality_and_entanglement