Descartes' Meditations on First Philosophy possesses a strong anti-authoritarian undercurrent, sharply dissimilar from the scholastic philosophy that preceded him. Descartes endeavors to establish a true belief set from an exclusively individualistic perspective, temporarily discarding anything from strict theology to simple sense perception in the process.
This Cartesian individualism, however, is less striking than it initially seems: Descartes' departure from the medieval mindset of his predecessors is incomplete, causing deeply entrenched concepts to doggedly interfere with the effectiveness of his philosophy as a tool for knowledge. Furthermore, even if his philosophical method were applied entirely without prejudice, considerable doubt arises as to whether it can lead to any useful conclusion.
Appealing to the logical claim that something must be true if it cannot be doubted, Descartes opens his essay by systematically suspending his belief in anything even remotely susceptible to doubt “just as though I have found it to be entirely false.” By asserting that all of his previous knowledge had come “either from the senses or through the senses”,Descartes' doubt of the senses represents a fundamental rejection of all knowledge he had acquired thus far.
Bringing into play a hypothetical “evil demon”, Descartes even finds grounds for rejecting basic mathematical knowledge as necessary truth. His eventual arrival at the statement “I am, I exist, [which cannot be doubted whenever] I state or mentally consider it”, a profoundly anti-authoritarian declaration, thus neatly distinguishes this individualistic assertion from all previous doubtable beliefs in an appeal to nothing but his own thoughts and existence.
At the heart of Descartes' philosophy is his effort to derive, from this inherently individualistic premise, an unshakable set of true beliefs. Compared to the questionable foundations of theological knowledge based intrinsically on appeals to authority, Descartes' thinking is undoubtedly ground-breaking. Indeed, it might seem that the proper application of this method is a sure-fire path to veritable knowledge: if something were derived from a proposition that cannot be doubted, the argument goes, how could it not be true? However, careful consideration reveals many of Descartes' arguments themselves to be anything but proper; in fact, it seems suspiciously as though Descartes himself appeals to authority to solve his more tricky problems.
A prime example is found in Descartes' Wax Argument, which he needs in order to establish that the mental images he experiences are not from the senses and can therefore be trusted. After observing a piece of wax melt in his hand, he concludes that the mind's knowledge of the wax is not based on any “physical sensation or imagination”, but instead on “understanding alone.” He bases this assertion on the fact that, when moved closer to the fire, the wax's physical properties change: he lists smell, colour, shape, size, physical state, hardness, and temperature. Descartes then generalises this case, stating that “what I have said about the wax applies to everything else that is outside me”.
From this mammoth leap, he then draws the extreme conclusion that he knows nothing through sensation or imagination, but instead through understanding alone, and decides that one cannot know anything “more easily or more plainly than [one's] mind”. It is understandable how this theory, closely mimicking Plato's forms, might seem obviously true to Descartes. However, without this implicit appeal to Plato - a dominant authority in the subject - it is difficult to accept this generalization in light of the fact that Descartes gives no real justification for why this must be the case. In fact, with this poorly hidden appeal, Descartes contradicts the very anti-authoritarian principles he established in Meditations I.
Descartes' explicit appeal to authority is even more problem-ridden. Unable to satisfy his problems of knowledge internally, he instead introduces a Christian God to his philosophy (using a host of dubious arguments that are not included in the scope of this essay) in order to solve this problem for him. Descartes writes that the “only reason for thinking that I ought to doubt these things was the thought that my God-given nature might deceive me.”
Then Descartes knocks down his own straw man, asserting that “it is obvious that He can't deceive, for the natural light reveals that fraud and deception arise from defect [which God, a perfect being, could not have].” It is worrying for a modern atheist reader to note that Descartes is left essentially dead in the water without God, that he can find no reason other than God's apparent benevolence to establish his set of true beliefs.
In fact, herein lies one of the most serious flaws with Cartesian Skepticism as a path to knowledge: by casting everything but thought itself into doubt, Descartes robs himself of any conventional tools to get back out of the mud of extreme skepticism, and is forced to rely on a multitude of complex and vulnerable arguments, each of which hinges on the next such that one flaw could conceivably bring down all the assertions that follow it.
