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Souls, Senses, and God: Perspectives from #Aristotle & #Descartes.

posted Nov 3, 2013, 4:14 AM by Peter Joseph Moons

Souls, Senses, and God:

Perspectives from Aristotle and Descartes.

 By Peter Joseph Moons


Aristotle and Rene Descartes discuss similar themes in their works De Anima and the Meditations on First Philosophy, respectively.  They both discuss the concepts of spirituality in terms of the soul, as well as knowledge, truth, and understanding.  Reviewed in the context of the culture and society in which they were written, the effects of society and organized religion weigh on the texts, thereby creating notable differences.  While Aristotle wrote in a time of pantheism, Descartes published the Meditations during a high point in the Catholic Church’s social, as well as political, power.  A major difference between the two philosophers lies in the essence of how each one knows what they do about the soul and how that affects their existence.  A second difference between these authors is their idea of the senses: Aristotle views the senses as inherent to animals, a techne,[1] and part of the soul, while Descartes sees the senses as separate from the soul and liable to deception.  Third, the idea of God, meaning an eternal, omnipotent, omniscient being is different for both men.  Thus, wherein Aristotle sees the soul, senses, and God (as the unmoved mover) as part of understanding the natural world, Descartes describes man as capable of error and God as perfect, which was in keeping with Church doctrine.


The Soul


            The discussion of souls in De Anima begins with an argument of whether the soul has potentiality or actuality, in an Aristotelian sense.  Aristotle states the soul has “potentiality”[2] but more importantly “affections” such as “emotion and fear.”[3]  He then argues that the soul is linked to the body, followed by a discussion of “perceptions” and “appearances.”[4]  Aristotle follows this by stating motivation for action comes from the soul.[5]  The evolution of this discussion is deliberate, and, as will be shown, Descartes repeats the process of evolution in his discussion on the soul, man, and God in Meditations.  In total, for Aristotle, the soul has potentiality of being, has emotions, which can perceive, and be deceived by appearances that are perceived, as well as direct the activities of the body.  Apparently, Aristotle was looking for an engine for the human body and categorized the soul as such.  Perhaps in antiquity this was both acceptable and appropriate.


            Being one of the earliest recorded philosophers, Aristotle’s social setting may have impacted the development of his writings.  In the city-states of Greece, where citizens judged each other, the modern reader may believe that he wrote with an eye on the potential acceptance of his thoughts.  An example that may have guided him was that of Socrates, who was put to death by his fellow citizens for corrupting youth, among other things, because of his speeches and teachings to those who would listen to him. 


Aristotle had no other knowledge of souls and bodies, emotions and perceptions than that which came to him from his peers and that which he theorized himself.  Aristotle could have imagined that only humans have souls; this linkage would have placed man at the top of the animal and plant kingdoms.  Instead, he argued that all living beings have souls.[6]  Was this a standard belief for Aristotle’s colleagues?  Was saying otherwise unorthodox?  Like his contemporaries in ancient Greece, Aristotle studied the natural sciences and he even refers to “the student of nature”[7] in his writings.  This natural science study is the one that Aristotle prefers,[8] versus the dialectics employed by the rhetoricians of his time.


            In understanding Descartes’[9] discussion of the soul, the influence of the Catholic Church cannot be underappreciated.  Descartes existed in the time of the Catholic Church’s power of determining what the punishment would be for communicating against the Church’s doctrine.  The offender would have went before an Inquisitor and if found in contravention to the doctrine, been punished by an auto-da-fe.[10]  So there is little or no divergence from Church teaching when Descartes states that his soul and body are one.[11]  He recognizes that the soul-body connection has the soul and body thinking, feeling, and being together. [12]  As noted already, this connectivity is somewhat different than Aristotles’ view.


What Descartes is describing is a form of duality: the mind (also meaning the soul) and the body inhabit the same space, but perform different functions.[13]  At the time of his writing, the Catholic Church also was engaged in finite discussions of the nature of God, of angels, and even how nature fit into the parameters of the religion, as witnessed by the Church’s treatment of Galileo before Descartes’ writing.  Descartes’ wondered about God’s creation of man.  He satisfies the conundrum of why a superior being would create an inferior one by his description of man being “finite in nature,” with imperfect knowledge, but at least capable of knowing that God is perfect.[14]  This may have been more than just Descartes’ analysis but also what the Church wanted to hear at the time of his writing.


The Senses


            Perhaps there is no surprise that Aristotle includes the senses in his treatise on the soul, much as Descartes does.  The most significant point that Aristotle covers about the senses are that there are perceptions and appearances.  He makes an important distinction: “Perceptions are always true, whereas most appearances are false.”[15]  Clearly, in his study of nature in antiquity, Aristotle and his peers saw that animals have camouflage, that weather can be deceptive, and that people lie.  An interesting point is that still there is a reigning thought that the perceptions of something by one person matter more than the intended statement or action by another.  In the time of the ancient Greeks, this bifurcation also existed, as Aristotle noted.


Certainly, not all animals are alike and each has different perceptions.[16]  Live beings have perception and that is what makes an animal an animal.[17]  Humans are different in this regard, and Aristotle first states that humans “know either by knowledge or by the soul.”[18]  The soul, he says, has emotions[19] and because of emotions, souls have bodies.[20]  Thus, no emotions mean the thing has no soul, and therefore no body.  Aristotle later refines this as he declares that “the soul is that by which we primarily live, perceive, and think.”[21]  So not only does the soul exist within living things as the driver for action, but also the filter through which appearances in the world are perceived.  This definition is an attempt to explain the how and why of human activity.


            Surprisingly, in the more modern writing of Descartes, as compared to the B.C.E. time of the ancient Greeks, the author also recognizes that his senses are not perfect.  Evolutionarily, man evolved little, if any, the intervening years.  That both authors decided upon the same conclusion about the senses of man, is no coincidence.  They did, however, arrive at this conclusion because of different social settings.  Wherein Aristotle and his contemporaries were known for their research and writing on the natural world, which led them to knowing that their senses could be deceived, Descartes likely came to this conclusion for two reasons.  First, experientially, he recognized he has both senses and emotions,[22] but he can only interpret them.[23]  Second, in the time of Descartes, the Church allowed followers to purchase indulgences, which were a method of alleviating sin.  Of course, the Catholic faith saw sin as preventing a believer from going to heaven.  Descartes’ acknowledgement that man was fallible and thus capable of sin was in line with Church teaching, and perhaps beneficial to the institutional nature of the Church in terms of ingress of funds from indulgences, remittances, donations, etc.


There really are two main points to take away from the Meditations concerning senses and knowledge.  The first is that God is “perfect and infinite,”[24] so the actions of God are perfect.  The second point is that man is capable of mistakes.  As Descartes notes, “I am nevertheless subject to an infinitude of errors.”[25]  At any time, his senses may betray him.  What Descartes’ logic does, though without stating so, is blame God for man’s low-order set of fallible senses.  The Church did not likely see Descartes’ argument as such.  In either case, Descartes, like Aristotle sees man’s senses as being deceivable, but in contrast to the ancient Greek, he also determined that because man lacks “reason,” he also cannot determine what is “true and good” from what is not.[26]  Essentially, he says, man commits moral wrongdoing because of errors in judgment.[27]  This ‘senses-morality-wrongdoing’ sequence goes beyond Aristotle’s input and evidently aided the Church, which benefited materially from the transgressions of its followers.




Aristotle’s “unmoved mover” is not defined by shape, for this entity was initially “moved by its own agency.”[28] Thus, the unmoved mover moved itself, and so is also not defined by action, other than movement.  The idea that something can move itself by its own consciousness would imply the unmoved mover was self-aware, at least enough to begin movement.  The “motion is everlasting,” states Aristotle.[29]  More important than movement is awareness, and with that comes knowledge and maybe even sentience.  So Aristotle has defined something, particularly something in nature that rationally caused the movement that resulted in the existence of all things.  Aristotle, in keeping with the logical understanding of nature he had, used inductive reasoning to explain the existence of the unmoved mover, which here can be synonymous with a god-like being.


Interestingly, Aristotle’s description of the unmoved mover is more organic than spiritual in nature.  He describes only what he can derive from logical analysis, seemingly devoid of speculation.  He does not discuss the reasons why the unmoved mover started the process, only that this was an eternal movement.[30]  Aristotle does note that the unmoved mover is sui generis: one mover is enough.[31]  The religion of the ancient Greeks was pantheistic, with gods for the elements of nature, the seasons, the harvest, etc., so when Aristotle sees the unmoved mover as one-of-a-kind, this is noteworthy.  The reason may be again in nature: humans can only sense one existence for themselves.  Thus, one reality requires only one unmoved mover to create this existence.


Descartes’ idea of God as a superior being differs from Aristotle’s view, though not in the idea that there is only one God, for they are the same in this regard.  Rather, Descartes describes God as an “all-knowing, all-powerful” creator[32] who is both “perfect and infinite.”[33]  Descartes makes the clear distinction that man can err, while God is perfect, and thereby incapable of error, deceit, or “malice.”[34]  So, man’s imperfection contrasts with God’s perfection.  This argument certainly sounds like the doctrine of a religion and not derived from the study of nature owing to the inferences, one could say, Descartes makes about God.


This reasoning by Descartes certainly would have been in line with Church teaching: Imperfect man can sin while God cannot, so if there is sin, man must seek absolution in order to become closer to God, who is perfect.[35]  Perhaps the most curious part of Descartes’ discourse on man within the Meditations, is not on the perfection of God, but the point that God gave man “free will.”[36]  With this statement, Descartes rationalizes the capabilities of man, as naturally observed, for choosing his own path in life.  Likewise with free will, humans make moral decisions, and sometimes fail due to their imperfect nature.  Ultimately, Descartes brings the discussion of God into modernity by connecting man’s imperfection to his inability to always choose good over evil, and doing so willfully, even though man was created by a superior, perfect being.




Aristotle and Descartes differ in their treatment of these three topics.  Aristotle provides the foundation in his study based on the concepts of form and nature.  Descartes, writing two millennia later, takes a more nuanced view of the soul, which is outside the body, and human senses, which can be deceived, likely influenced by the doctrine of the Catholic Church.  Both writers see God as separate from the existence of humans, as always existing, though Descartes provides more detail as to God’s involvement in the creation of man directly.  Worth noting is that the Catholic Church was at a heightened state of power in the middle of the second millennium, C.E.  While there was not the debate that is seen today in terms of spirituality versus religion, there was some negativity by Europeans about the oppressive nature of the Church.  So there is little surprise then that Descartes does not discuss religion directly but attempts to understand how man is fallible.  The Catholic Church of his time saw humanity in a similar light.

[1] Aristotle, De Anima (Indianapolis: Hackett Publishing, 1996), 414a14.

[2] Ibid., 414a25.

[3] Ibid., 403b18.

[4] Ibid., 428a passim.

[5] Ibid., 433a passim.

[6] Ibid., 413a20-25.

[7] Ibid., 403a29-403b9.

[8] Ibid., 403b11-13.

[9] The Turabian guide version 7 states that the possessive of Descartes is “Descartes’” and this paper uses that possessive.

[10] Voltaire, Candide, Chapter 8. (Accessed October 6, 2013) Voltaire has a satirical plot point on the subject of auto-da-fe.  

[11] Rene Descartes, Meditations on First Philosophy, Simon and Brown, 2011, 77.  (This Simon and Brown edition does not provide the city of publication, thus I have not written one.)

[12] Ibid.

[13] Prof. Condella, PowerPoint slideshow on Descartes’ Meditations.

[14] Descartes, 79.

[15] Aristotle, De Anima, 428a12.

[16] Ibid., 413b30-414a4.

[17] Ibid., 413b1-2.

[18] Ibid., 414a7.

[19] Ibid., 403b18. He refers to these emotions as “affections.”

[20] Ibid., 403a17-20.

[21] Ibid., 414a13-14.

[22] Descartes, 71.

[23] Ibid., 78.

[24] Ibid., 45.

[25] Ibid., 53.

[26] Ibid., 56.

[27] Ibid., 57, and Prof. Condella, PowerPoint slideshow on Descartes’ Meditations.

[28] Aristotle, Physics, 250a20.

[29] Ibid., 259a7.

[30] Ibid.

[31] Ibid., 259a7-8

[32] Descartes, 44.

[33] Ibid., 45.

[34] Ibid., 52.

[35] Ibid., 85.  Descartes says in the last paragraph of Meditation VI that he is sometimes deceived by what he sees because of his imperfect “nature.”  This modern view accepts man and his condition. The Church would agree that man, owing to his bad judgment and moral fallibility, can sin, but wants man to both pay for his sins and do better in the future by avoiding sin.  The Church knew that sin could not be eliminated, though, only absolved until the next time.

[36] Ibid., 57.