On Descartes and Skepticism

A comparison of Descarte's skeptical rationalism to Platonic thought

On Descartes and modern philosophy

Descartes' thought was a precursor for the scientific method. He challenged the dogmatic worldview of the time which was steeped in Aristotlean metaphysics. In doing so, he established the unreliability of sense knowledge, thereby affirming skepticism as a basis for truth. Therefore, Descartes was first and foremost a rationalist, relying on abstract reasoning to conduct his scientific investigations.

Descartes is further remembered as a thinker who kicked off the modern age, by introducing the individual subject as the foundation of all knowledge. This development was positive in that it allowed for the removal of religious tyranny. However as this essay will show, it also introduced into the culture a misunderstanding in it's break from Platonic thought.

On Cartesian rationalism

Descartes' form of rationalism employed skepticism to arrive at what could be known with absolute certainty. His method examined all information received from his senses for any seed of doubt. This allows him to defend himself from his hypothetical 'Great Deceiver', who could cause him to think falsely, and not allow him to recognize the deceit. In the end, Descartes concludes the first idea of which he is absolutely certain, and that is in order for thought to exist, there must be a thinker. This conclusion is summed up in his famous dictum 'I think therefore I am'.

On the similarity of Descartes to Plato

Descartes relies heavily on Platonic ideas to draw out his reasoning. As mentioned, both philosophers agree that our senses deceive. Descartes labels all sense impression a form of belief, being incapable of reaching knowledge of an object's essence. He reserves this ability for the mind alone, noting that it is through a process of understanding that we come to clear knowledge about an object.

Descartes allows that ideas have an essence of themselves, independently of the thinker. In discussing triangles, he mentions how triangles have a self-evident property of possessing 180 degrees. He is in agreement with Plato that we possess an innate knowledge of such ideas, and that coming to understanding regarding them is recovering knowledge we already knew.

Descartes relies on this argument to present his proof regarding the existence of God. He states that though we are imperfect beings, we can conceive the idea of the perfection. He mentions we cannot be the cause of such an idea, since we are not an infinite and perfect being. He then asserts that God must exist, as the source of this idea of God within us. Descartes concludes that a benevolent God would never willingly deceive him, thereby assuring that truth and scientific progress is possible. Any deception therefore arises from misusing one's faculties in ways not intended by God.

On the difference between Descartes and Plato

In summary, Plato and Descartes have similar ideas regarding the process of understanding, and the existence of God as the overarching cause for existence. Their thoughts diverge however, when examining the relation between God and human understanding.

Plato regards the relationship between man and God as participatory, with the nature of one both sharing in the other. In the Republic, Plato presents the Analogy of the Sun to illustrate this. It is through the eye that a human possesses sight, however it is the Sun that is the source of light that enables seeing. In a similar way, it is the One that is the source of the soul's understanding. The soul is not enabled to move from the darkness of ignorance to wisdom except by the light of the One itself. The One is both a cause and an object of knowledge, therefore it is by remaining turned towards the Good that growth is enabled in the soul.

It is crucial to note however that whereas Plato equates the two, Descartes considers the activities of the mind and soul to be entirely separate. So while Plato considers growth in understanding to lead to growth in the soul, essential to bringing one closer to God, for Descartes the entire process is reduced to a mental enterprise.

Plato expands on the relation between mind and God through the Analogy of the Cave. He compares the human condition to that of a prisoner shackled in a dark cave facing a wall. Overhead there shines a bright light with objects passing through ahead. Not knowing any better, he points out how man believes the shadows on the wall to represent reality, rather than the objects themselves.

Descartes touches on this when laying out his theory on thought, which he labels representationalism. He notes how we only have access to our mind. As the world outside is entirely separate from us, our thoughts, impressions and sensations regarding the world can only be a representation for the object they refer to. In short, we know the object's shadow but not the object itself.

But whereas Plato believes both participate in the other by analogy, Descartes believes the representation and object are entirely separate. In a related fashion, he then goes on to reject the idea that God can exist within him in some potential form. It is clear that for him, God is a mental abstraction, something that may be reasoned about in the same sense as discussing mathematical proofs and figures. It is no longer a concept that can be participated in for the good of the Soul, which is readily apparent as explained earlier, now that Descartes has separated the functions of the mind and the soul.

On man as the foundation of knowledge

Descartes kicked off the modern period by resituating participation in God as the highest human principle, to instead being situated in the mind. Man now firmly serves as the foundation of all knowledge. This shift in worldview is significant. Whereas Plato understood knowledge to be innate and always available to us, Descartes understands the Divine that might enable knowledge to be entirely absent, and instead it is entirely the responsibility of Man to drive progress forward.

To conclude, it is clear this worldview drives the entire drama that Descartes describes in his Meditations. His drama is described entirely from the first person perspective. By exploring his faculties in such detail he breaks from the accepted tradition of the classic world, but at the same time lets in the daemon to haunt his every thought and action. It is clear that such a daemon can only result from a world devoid of unity. It is clear also that it is this very same daemon that infects our culture with anxiety and lack of meaning which no amount of scientific knowledge can replace.