Introduction Throughout the 17th and 18th
centuries, two schools of thought dominated philosophical inquiry: Continental Rationalism and British Empiricism. This paper will be concerned with comparing a representative from each school, Rene Descartes and David Hume, respectively. Although each philosopher built upon a different epistemological foundation , the philosophy of each is marked by skepticism, arbitrariness, and presuppositional inconSistency. Neither allows his philosophy to be founded upon and shaped by the self-attesting Word of God. Three key thrusts in their philosophy will be compared: epistemological method, substance and interaction, and the existence of God.
Epistemological Method Rene Descartes (1396-1650) Descartes craved absolute certainty.
"1 always had an excessive desire to learn to distinguish the true from the false, in order to see clearly in my actions and to walk with confidence in this life." His primary goal was to pursue a certain, well ordered philosophy. ' Descartes' ideal of philosophy "was that of an organically connected system' of truths, that is to say, of truths so ordered that themind
passes from self-evident truths to other evident truths implied by the former" (Copleston 69).
Descartes, like the other Rationalists, believed in innate ideas. "Those propositions are both certain and true which present themselves dearly and distinctly to reason orman's consciousness" (Sahakian 13 7). These innate truths represent eternal truths and do not reqUire the verification of sense experience. Descanes held that since our senses "sometimes deceive us," we could not build a cenainsystem of philosophy on our sense perceptions. -Descartes identified five innate truths: God, ex nthtlo nihil fit, the law of noncontradiction, what is done cannot be undone, and dubito, ergo sum. Innate ideas coupled with mathematical fonnulas give us objective truth about the real world.
In order to achieve certainty, Descartes pursued methodological doubt. He set out to doubt everything which could possibly be doubted. He conduded with his famous statement, "Dubito, ergo sum." "I doubt, therefore I am." Descartes was cOnvinced that the self was the only foundation upon which man could construct a certain philosophy. God and the material universe could be doubted, but in the very act of doubting . these, man's existen.ce is confirmed. The self, then, is "the indubitable truth on which
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Descartes proposes to found his philosophy" (Copleston93). Implicit in this reasoning is the unproven assumption that thinking requires a thinker.
Having laid the foundation for his philosophy, Descartes "came to the conclusion that I (he) might assume as a general rule that the things which we conceive very clearly and distinctly are tjUe." (Descartes,Meditattons 3) What did Descartes mean by "clear and distinct" ideas? "BUt the distinct is that which is so precise and different from all other objects that it contains within itselfnothing but what is clear." These clear and distinct ideas are known by intuition, "by which is meant a purely intellectual activity, an intellectual seeing or vision which is so clear and distinct that it leaves no room for doubt." (Copleston 73) From these intuitively known self-evident truths, we can deduce other truths which are also certain.
Descartes' philosophy was a dear break with the Aristotelianism of the past, and opened the door to the skepticism of the future. By making the mind of man the starting point of his philosophic system, Descartes revolutionized philosophy by subjectivizing philosophy.
"Indeed, the fact that his quest for absolute certainty should first lead Descartes to the self, that its existence J:,ecame the premise of his whole philosophy, was at once a symptom of the enormous change that had already occurred and a fotecast of the subsequent course of philosophic thought." Oones 668)
David Hume (1711-1776) With John Locke and George
Berkeley, Hume loathed the "abstruse speculation" of the learned. In order to free learning from these speculations, Hutne believed that "we must enquire
. seriously into the nature of human understanding." HUme was most
anxious that philosophical problems not be resolved by appealing to superstition and "metaphysicaljargon."
John Locke had already denied the innate ideas of the Rationalists. "Berkeley had denied the validity of any ideas abstracted from sensory experience" (Sahakian 161). It was now up to Hume to take his predecessors' empiricism to its logical conclusions. He denied that we lmow anything except our immediate sense perceptiOns. Hume held that it is impossible to know if there is anything beyondoursenseimpressions. "Hume was a thoroughgoing skeptic concerning the possibility of achieving certainty" (161).
We have already noted that Descanes pursued methodological doubt as the foundation for building his philosophical certainty. In his Enqu.iry, Hume comments on and destroys Descartes' method. While a moderate skepticism, doubt, is necessary if we are going to be objective in our philosophical pursuits and free ourselves from prejudice, a universal doubt of all our faculties and beliefs is destructive to that verycertaintywhich Descartes was trying to demonstrate.
There is a species of skepticism, antecedent to aU study and philosophy, which is much inculcated by Descanes and others, asa sovereign preservative against error and precipitate judgment. It recommends a universal doubt, not only of all our former opinions and principles, but also of ourvery faculties; of whose veracity, say they, we must assure ourselves, by a chain of reasoning, deduced from some original principle which cannot possibly be fallacious or deceitful. But neither is there any such original principle, which has a prerogative above others, that are self-evident and convincing; or if there were, could beadvanced astep beyond it, bu.t by the use of those very faculties, ofwltich we are supposed to bealready
diffident. The Cartesian doubt, therefore, were it ever possible to be attained by any human creature (as it plainly is not) would be entirely incurable; and no reasoning could ever bring us to a state of assurance and conviction upon any subject (Hume, Enquiry XII, i, emphasis mine).
Hume believed that all the perceptions of the mind could be divided into two classes: thoughts, or ideas, and impressions. All ideas are copies of sense impressions. The difference between the two is that our impressions are more vivid than our Ideas of those impressions. Hume denied that ourideas give us any object knowledge of the external world. We only know our impressions of the external world. Hume challenged all truths except those of mathematics and our sense perceptiOns. Whereas Descartes believed that innate ideas and mathematical formulas give us knowledge about the real world, Hume denied this, and held that what we lmow through our senses only tells us how we think, speak, and live, but can tell us nothing about the external universe, the self, or God.
Before moving on to their doctrine of substances and interaction, some concluding remarks seem appropriate. Descanes began with skepticism, and Hume concluded with skepticism. Descartes, with all of his disdain and distrust of the senses as the right foundation for philosophical speculation, retreated into the inner recesses of the self to develop this objective certainty . . He was both rational and irrational. He denied the reliability of his senses imd yet based his entire philosophy upon them.
The same can be said ofHume. He rationally condemns the very rationality which he abhors. Hume cannot pursue empiricism and skepticism without at the same time using his reason to determine that the
only thing he can trust are his senses. Thus, Hume's "Empirical Criterion of Meaning" does not pass its own imposed "criterion of meaning." Van Til has rightly said that within all unbelieving thought, there is a rationaV irrational dichotomy. The unbeliever irrationally (subjectively, skeptically) believes that man cannot know anything about ultimate reality. We are surrounded by absolute mystery. At the same time, he is dogmatically rational (objective, certain) when he claims that what the Bible says about ultimate reality cannot be true. The unbeliever has faith in ultimate mystery and ultimate rationality at the same time. However, one cannot have one's cake and eat it too.
Substances and Interaction Rene Descartes
Descartes believed all that is real is either a substance or an attribute of a substance. A substance is "a thing which exists in such a way as to stand in need of nothing beyond itself' (Descanes, Principles of Philosophy). Descartes held that whenever we perceive an attribute of a subStance, heat, light, white, or black, there is a "present, unperceived substance." We do not perceive the substances themselves, but only the substances' qUalities.
Moreover, Descartes was a dualist. He taught that the universe is composed of two distinct and independently separate kinds of substances: mind and matter. There exists a thinking substance, the mind, and an extended substance, matter. This theory is known as Cartesian Dualism. This dichotomizing of mind and mailer makes certaintyim possible.
How do these two types of substances interact? While we perceive qualities of the substance, how can we from those qualities infer that the actual substance exists in the real world? It is here that Descartes was dependent on God, who created the universe, and
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