In the first meditation, Descartes calls everything into doubt that can be reasonably doubted. Descartes’ goal is not a wholesale denial of reality, but rather a careful attempt to re-examine presuppositions in order to assess whether they are justified.
His overall project is to find whatever causes of error there might be, so a methodology for the elimination of error might be developed; and, in the process, one can demonstrate the existence of our souls and of God.
He begins by dismantling the foundations and assumptions of knowledge to the most basic level, to start from scratch:
And thus I realized that once in my life I had to raze everything to the ground and begin again from the original foundations.
He calls his senses into question, and assumes the possibility that all he perceives now might be a mere dream.
Let us assume, then, for the sake of argument, that we are dreaming and that such particulars as these are not true: that we are opening our eyes, moving our head, and extending our hands. Perhaps we do not even have such hands, or any such body at all.
As to the laws of logic and arithmetic, they might as well be products of an evil god or demon who wants to deceive him. If God is good, he would not deceive his creatures, he ponders. But he recognizes that he occasionally makes mistakes, and so it might be possible that God is not so good or incapable of deceiving.
In the second meditation, Descartes realizes that he can only doubt or be deceived if he exists. He concludes that the only thing that he cannot conceptually separate from his existence is his own thinking. Therefore, he is at least a thinking thing.
He investigates his perception of wax: it has a certain color, shape, etc. But if he brings it close to the fire, it loses those properties; but he still understands it as wax. Descartes concludes that the wax could take more shapes than he could imagine and still be wax to him, which shows that he grasps the wax not with his senses or with his imagination, but with his mind alone. Once again, the fact that he grasps with the mind demonstrates minimally that he exists, that he is a thinking thing:
But what then am I? A thing that thinks. What is that? A thing that doubts, understands, affirms, denies, wills, refuses, and that also imagines and senses
In meditation three he argues that everything he sees clearly and distinctly is true, since he sees that he is a thinking thing in that way. Logic, arithmetic and geometry are within that realm. The only basis for doubting them is the postulation that there might be a god who is deceiving him. So the question becomes, is there a god, and if so, is he a deceiver?
Ideas differ from one another in their objective existence, in that ideas of a substance have more objective reality than ideas about non-substances. Therefore, the idea of the greatest substance (God) has the greatest objective reality.
Hence, things exist in the intellect objectively and they are plainly not nothing. Therefore, the causes of such ideas have to have formal modes of being.
There are three classes of ideas:
(ii) corporeal and inanimate things;
(iii) angels, animals and other things.
Ideas of (iii) could perhaps come from other ideas of God and himself. (ii) could also come from him (as related to substance, duration, number, etc.) But the idea of God is the idea of infinity and perfection, and so could not have come from finite and imperfect Descartes.
Therefore, his idea of God, with the greatest objective reality, must derive from a real cause, a real God who exists, And this God has such a nature that it is impossible for Him to deceive.
I understand by the name “God” a certain substance that is infinite, independent, supremely intelligent, and supremely powerful, and that created me along with everything else that exists . . . Indeed all these are such that, the more carefully I focus my attention on them the less possible it seems they could have arisen from myself alone. Thus, from what has been said, I must conclude that God necessarily exists . . . From these considerations it is quite obvious that he cannot be a deceiver, for it is manifest by the light of nature that all fraud and deception depend on some defect.
In meditation four, the idea of God is the most clear and distinct he has, and that He cannot be a deceiver. In his goodness, He has given Descartes faculties that, when used properly, cannot make mistakes, But he (Descartes) does make mistakes, and that is the problem. Descartes acknowledges that his intellect is not complete. God has created him with free will – complete because it has been given according to the image of God.
It is only the will of free choice that I experience to be so great in me that I cannot grasp the idea of any greater faculty
Genuine free will cannot be given partially. It is the simultaneous work of his intellect and his free will, when the latter outstrips the boundaries of the former, that allows for error; that is to say, the problem is not with cognitive capacities in themselves, but with the will. However, since the will causes the intellect to go astray, without clear and distinct understanding, one should withhold judgment.
What then is the source of my errors? They are owing simply to the fact that, since the will extends further than the intellect, I do not contain the will within the same boundaries; rather, I also extend it to things I do not understand. Because the will is indifferent in regard to such matters, it easily turns away from the true and the good; and in this way I am deceived and I sin . . . For as often as I restrain my will when I make judgements, so that it extends only to those matters that the intellect clearly and distinctly discloses to it, it plainly cannot happen that I err.
Meditation five shows that he has the idea of God in a no less clear and distinct way than the ideas of mathematics. The existence of God has to have, then, the same degree of certainty as mathematical truths. Existence is conceptually inseparable from the concepts of God, which presumably shows that God must indeed exist. He knows God exists based on his clear and distinct idea, and, since God is the one who gives infallibility to the “clear and distinct,” such concept allows him to achieve full and certain knowledge of countless things (which seems circular):
Even if I were dreaming, if anything is evident to my intellect, then it is entirely true . . . now it is possible for me to achieve full and certain knowledge about countless things, both about God and intellectual matters, as well as about the entirety of that corporeal nature which is the object of pure mathematics.
Meditation six allows for the rest of the universe to come flooding back in. Since he exists, and God also exists and is not a deceiver, his ideas of everything else are not fabricated by God, and must therefore be caused by the corporeal things. His senses are not infallible, but he can correct them by what he clearly and distinctly perceives.
Descartes argues for the commingling of the body and mind, where mind is simple, indivisible, and the body is complex and divisible, being therefore distinct. This becomes the basis for Cartesian dualism:
There is a great difference between a mind and a body, in that a body, by its very nature, is always divisible. On the other hand, the mind is utterly indivisible … this consideration alone would suffice to teach me that the mind is wholly diverse from the body.
According to Descartes, the body and the mind communicate through the pinary gland in the brain. The sensations that come from different parts of the complex body might admit error as they reach that part of the brain, but memory and intellect are able to keep them in check.
In the first meditation, Descartes seems to be bound by his own doubts. He states that he will doubt everything that can be reasonably doubted, and goes as far as to say that he might be mistaken every time he adds two and three, or counts the sides of a square.
If indeed there might be an evil God who will cause Descartes to be mistaken in “arithmetic, geometry, and such other disciplines” (presumably logic), even if they seem to be certain and indubitable, how can he reasonably doubt everything? Descartes has to choose whether reason can be relied upon in any sense, before he can reasonably doubt reason.
Furthermore, the entire foundationalist structure for Descartes’ epistemology is one belief: “I think.” This seems a rather thin foundation. Can this classical foundationalism yield enough justification from one belief to a multitude in the structure?
Therefore, it seems that his project is destined to failure from the start. He could doubt, but he does not seem to realize that he could also doubt his doubt. This will also be overlooked later as Descartes relies on the infallibility of what is “clearly and distinctly perceived.” The result is that what became more or less the birth of Rationalism in the West had intrinsic problems from the start.
Descartes’ desire to construe a foundation for epistemology based solely on autonomous human reason was not revolutionary, but a natural product of the incipient modernism of his time. His influence spanned through centuries, and it was not until relatively recently that epistemology began to doubt its own capacity to achieve Cartesian certainty if the proper procedure was meticulously followed.
Up until the time of the beginnings of modernism, thinking in the West followed an epistemology of analogy, where God and the world were known in the proportion that finite human beings could know: truly, and yet finitely, recognizing that created reality was a participation in existence given by God. Now, the mode of knowledge was switching to an univocal approach; later, postmodernism would turn to an equivocal epistemology.
Of course, both during his time, as well as later, some had already pointed some logical flaws on Descartes’ arguments. However, his project opened up avenues for the more systematic separation between revealed dogma and pure reason – which was taken up by Kant.
From that time, philosophy could become in principle a separate realm from theology, and epistemology relied on the primacy of reason and intuition over sensation and experience, regarding all or most ideas as innate; as a result, there was an emphasis on certain knowledge (rather than merely probable) as the goal of inquiry. There was great optimism in regards to the future of mankind, physical sciences were beginning to take great leaps, and the expectation gained ascendancy that certain knowledge not only could but should be achieved free from any constraints of ecclesiastical authority.
Naturally, this also found expression in the reverse direction, in the very realm of religion – particularly in the work of the Reformers, who had a much more modest place for traditional authority than Rome, and so examined Scriptures through reason and, presumably, the illumination of the Spirit.
But of course, ultimate reality was revealed by sola scriptura, and the Scriptures meant not necessarily what the Church had passed through Tradition, but, in good humanistic fashion, what the appropriate methods of interpretation, with the correct linguistic training and tools, would yield. Cogito, ergo interpreto.
As history progressed, eventually the unifying center of reality for the Enlightenment and modernity was autonomous human reason; both broke with the medieval assumptions about authority and epistemology, even though in different ways, but both also substituted their own paradigms as their epistemological authorities.
It was not until recent times that Postmodernism sprung up as the pendulum began to swing the other way. However, as I have pointed in another article, Postmodernism, while bringing much needed correction to modernist assumptions, could not escape retaining its individualistic bent.