Rene Descartes is known for the most well-known quote in all of philosophy, “Cogito, ergo sum” – I think, therefore I am. Apparently, when he wrote this in the 17th century he was unaware that over ten centuries before St. Augustine had made the same point. Rene’s friends let him know about the work of St. Augustine. In a letter Rene wrote in November 1640 from Leiden in the Netherlands, he said:

“I am obliged to you for bringing to my notice the passage of St. Augustine to which my Cogito ergo sum has some relation. I have been to the town library to read it; he does, I find, really use it to prove the certainty of our existence.”

In another letter from Leiden, May 2, 1644, to a “Father Mesland,” he says:

“I am much obliged to you for telling me of the passages in St. Augustine that may serve to give authority to my opinions; some of my other friends have already done this; and I am exceedingly gratified that my thought is in agreement with such a holy and distinguished personage.”

Augustine and Descartes

There are similarities between St. Augustine’s “Si fallor, sum” – If I am mistaken, I am – and Rene’s Cogito; and these similarities are not limited to the words themselves. Where this thinking conclusion takes both thinkers is similar, and for each of them their final “destination” is God.

St. Augustine arrived at his “Sum” conclusion in response to a philosophical position known as “skepticism” – the view that says that no knowledge is possible beyond what one knows by immediate sense experience, and, in some extreme positions, that even knowledge based sense experience is impossible. In his famous City Of God, St. Augustine wrote this about the “Academicians” who said knowledge was not possible: “I am not at all afraid of the arguments of the Academicians, who say, ‘What if you are deceived?’ For if I am deceived, I am.” (De Civitate Dei, Book XI, 26).

An “Inward Turn” To The Self

Rene Descartes make an “inward turn” to the self in an effort to overcome those who say you can know nothing. But once they arrive at this “self,” they also realize that this is simply a logical/rational dead end – all that has been concluded is that this “self” exists. What about anything else? What about anyone else? Solipsism may be logically defensible – the view that all that can be known is one’s self – but it can lead to the conclusion that other persons do not exist and the material world does not exist. Both thinkers found these conclusions unacceptable.

So, how did they establish the existence of things and people beyond oneself? Both thinkers turned looked outward, turning away from the inward self, to God.

For St. Augustine, it is by the illumination of God, by “divine light,” that we can have knowledge. In a work entitled Contra Academicos, Against The Academicians, he says: “only some divinity can show man what is true.” The shining of this “divine light” on things and persons, for St. Augustine, makes possible the knowledge of them:

“But distinct from [the objects of the intellect] is the light by which the soul is illumined, in order that it may see and truly understand everything, either in itself or in the light. For the light is God himself, whereas the soul is a creature; yet, since it is rational and intellectual, it is made in his image. And when it tries to behold the Light, it trembles in its weakness and finds itself unable to do so. Yet from this source comes all understanding it is able to attain.” (Literal Commentary on Genesis, XII).

In a similar way, following a similar path after he had reached the conclusion “Sum,” I am, Rene Descartes also realized that the “self” he may have proven to exist stood on shaky ground as far as the proof of the existence of other persons and the material world. Descartes proceeds from the existence of the self to the existence of God (an argument not discussed here). He then notes: “It remains for me to examine whether material things exist.”

God Is Good

Descartes resolves the question of the existence of the material world using as his basis the fact that God is good, and He is not deceiving, the God of truth; and since he has ideas of corporeal objects, they must exist:

“For God has given me no faculty at all to discern their origin; on the other hand, he has given me a strong inclination to believe that these ideas proceed for elsewhere, not from corporeal objects. Therefore, corporeal objects must exist . . . And I need not doubt the reality of things at all . . . In such things I am nowise deceived, because God is no deceivber.” (Meditation VI, Meditations On First Philosophy).

Today in this world for many the ideology of the self is all that makes sense – and it leads nowhere except to a type of eat-drink-be-merry sensualism that precedes death, beyond which there is nothing. Perhaps it would be profitable – i.e. eternally profitable – for the devotees of the self-ideology to follow St. Augustine and Rene Descartes down the road to “self,” arrive at the dead end to which it leads, and then go on with them and see how and why the road leads to God.