Descartes' Method of Doubt



1.Descartes and the Church

2.Descartes' method of doubt


Okay, we have decided to do some philosophy in the form of epistemology (some metaphysics will come with the package, also). We are going to try to discover what constitutes knowledge (ideas which are absolutely certain or self-evident --in a nutshell, the TRUTH). We know that we will use consistency, completeness and pragmatism as principles to scrutinize and emend our beliefs. But, we need a bit more for a directed study; we need a method universally available to all of us that will help us get to the truth quickly. After all, scientists have their scientific method and laboratories, why shouldn't we? We need a research method and lab in which to do our testing. We need a thought-experiment to help us find out what may constitute knowledge.

1. A quick look at the reasons someone else (Descartes) searched for certain knowledge; can science be compatible with religion?

One of the good things about doing philosophy is that certain methods come with their own labs. Sounds unlikely, doesn't it. But, it's the truth. We are going to utilize a method and corresponding "lab" developed by a philosopher named Rene Descartes who was a seventeenth century philosopher. Before I explain what method and lab Descartes perfected, let me tell a little about the philosophical problems Descartes faced so that we can see what prompted his thoughts. I'm going to splice together and oversimplify a lot of history of philosophy to save time, but I think that we will be able to see more clearly the general issues that were surfacing in the 15th and 16th centuries and why Descartes did what he did.

Remember, as we are, Descartes was after knowledge --what is the truth (that which is absolutely certain) about matters.

From the middle-ages to the Renaissance, what counted as knowledge or truth was revealed knowledge. Epistemology or the study of the nature of knowledge boiled down to what God revealed about His works to man. God, speaking through the Scriptures and the Church, told man about the world --how it came into being, what it consisted of and how he ought to live in his environment. Man was considered to be a part of the created world, a very important part (the universe revolved around earth), but his place in the scheme of things was as a creature who was passive with respect to knowledge; God would reveal to man through the Scriptures only what man needed to know.

For example, the origin of all living things, including man, is explained in the first book of the Bible, Genesis. Man and other living things did not evolve, we are told, but were created outright. The exposition in the Scriptures was considered to be complete with respect to its sufficiency in explaining the creation or existence of the world and all of the things in it. So, if a person wanted to establish a method for learning about the world, he needed to go no farther than reading the Scriptures. And, what was revealed through that reading constituted knowledge upon which the person could base his actions.

However, as we well know, humans have virtues and vices, especially curiosity and greed. Both were responsible for the coming into being of modern science. The advent of quality glass, telescopes and microscopes enabled man to look at the world telescopically and microscopically and puzzle over it. Man began to ask questions about the nature of these new found aspects of the "old" world. The more he asked, the more instruments he invented to find out answers. Man's curiosity began to run wild; he began to investigate everything. Radical events occurred: the earth was found to be round, not flat: it was discovered not to be the center of the universe, but one planet among many in a solar system; capillaries were seen and the circulatory system explored; rudimentary printing presses made the distribution of data more available; and much more. Man, on his own, began to find answers to questions which were not answered adequately in the Scriptures.

Human greed was at work too. Early chemists (alchemists) worked non-stop to try to figure out how to make gold out of other substances. They never succeeded, but the birth of chemistry occurred. And with it, new materials which had practical use, sometimes terrible use --gunpowder. Actually, gunpowder came from Asia, but Europe was able refine it and use it in remarkably destructive ways. These materials were classified according to their functional use with other materials, and as such, could be given a quantitative, functional definition (mix so much x with y to get z; z is x + y). (I'll leave it to you budding chemists to figure out how much and what ingredients are needed to make beer.) More and more, the world of materials was being thought of in quantitative terms.

At the bottom of all this was the fact that as man began to investigate and tinker with nature, he discovered that he could actually do things to nature. He could dam up streams, control agriculture, navigate oceans, and cure diseases. Man no longer simply lived in a world that escaped his understanding and control; his knowledge of the world was no longer passive, but active --he became an agent in the world, able to change it according to his wishes.

The 17th century exploded with man's discovery of his intellectual powers and his realization that he was learning how to control nature itself. Knowledge no longer consisted of truths revealed to man, but ideas which he constructed through the powers of his own intellect. Man had discovered the powers of his own mind to use on nature. He could investigate the world with the aid of the light of reason. Reason would light up the principles of nature to be discovered and used.

But what was this new world which was being discovered by man's intellect? Was it composed of Earth, Fire, Air, and Water as had been passed on since the early Greeks, or was it something entirely different? What were the "elements" which were at the bases of the alchemists' experiments? The four Greek "archai" or elements did not begin to satisfy the notion of chemical change. What was needed was a new conception of the basic substance which made up the world --the that out of which all things are made-- so that chemical change could be explained and predicted.

And a new substance was found. (Well, for all practical purposes the concept was new; actually, the bases for the new concept go back to the Pre-Socratic philosophers --circa 500 BC-- believe it or not.) The world was conceived as being constituted by small quantitative items (atoms: things so small they were "uncuttable" or indivisible) which were universally the same in quantitative characteristics (extension, motion), but different in qualitative characteristics (color, taste, smell, warmth and so on) depending upon their arrangements. To be more precise, the atoms had no qualities in themselves, but somehow produced qualities in the sensing creature --in this case, man. Atoms, being strictly extended stuff, had no color, but their configuration with one another could cause color to appear in a person's mind.

This new conception of matter is very radical --something on the order of switching from Bach to the Rolling Stones. Previously, matter played a secondary role to things such as minds, ideas, social and political systems. Now, atoms became the basic building blocks, the substance out of which all macroscopic things were constructed. Matter was seen to be unchanging, extended substance; bodies were small bits of extended bulk that changed position through motion and rest. Understanding the world and, of course, any part of it (man) meant that one had to understand the nature of atoms; the "explanatory buck" stopped with the atom.

With the advent of the conception of atoms as the primary substance, there came also another conceptual breakthrough; man needed a new language to talk about this quantitative substance, this new world of atoms in motion. A language, which was as precise as the quantitative substance was in its exact dimensions, was deemed necessary. The result was the birth of modern mathematics. Mathematics was considered to be a precise language; one could not make a mathematical mistake without being called into error by any rational thinker. By contrast, the old language about the world was basically qualitative --people could disagree strongly over why the world came into being and its aesthetic characteristics (its beauty), yet never really contradict one another. The old language of purposes (teleology) and qualities just wouldn't do; scientists were not interested so much in why a rock fell to the ground or that the rock had a beautiful color, but whether or not all rocks fell at the same rate and how to measure that rate and state those results in precise terms so that others could confirm the data. What language, scientists and philosophers asked, could be accurately thought in the mind and also conform precisely to the material of the world?

To repeat, the solution was obvious; let mathematics be the language about the atomic world. Why? Because both are essentially quantitative. The two made a perfect fit; mathematics could belong to both the world of ideas and the world of bodies. How so?

Mathematics was pure as conceptual formulations in the mind. When one did geometry correctly, he could not be mistaken without falling into contradiction. How could a square be said to be round without contradiction? Theorems in geometry could be proved deductively from self-evident premises, premises based on conceptions that no rational thinker would challenge. Who, for example, would think that there could be more than one straight line between two points on a plane surface? Geometry, the mathematics of extension conceptualized, became the descriptive language of the atomic world. To talk geometry was to talk physics. If a square was 2 meters on each side then the area of the square had to be 4 square meters. If a regular cube with sides of 1 meter were pushed at 1 meter per second on a plane surface, then in 1 second the cube would travel 1 meter and would occupy (in terms of elapsed time) 2 square meters. The fit of the language of geometry to the atomic world was perfect. If atoms were extended (geometrical) bodies, then the language of geometry could adequately (this word is important: 'ad equatio', which means, "equal to") or precisely describe the atoms. And that meant man could have an exact language which could lead to true knowledge of the atomic world and its behavior. All man needed to do was to "read the great geometrical book of the world" through experimentation guided by reason to gain knowledge of it. Moreover, he could do so without the need of revealed knowledge. In other words, more and more, God was being left out of the picture in scientific discourse.

Needless to say, the Church was terribly threatened. If man no longer needed God to understand the world, then religion and the power of the Church to affect the beliefs and actions of man were in big trouble. So, the Church set about to coercively suppress science and mathematics.

Descartes was a prominent thinker during this turmoil. He was, besides being a philosopher, a brilliant mathematician. (Ever heard of Cartesian coordinates?) He was a firm believer in the power of human intellect to find truth and had many friends who were of the newborn scientific community. He worried about their safety, for many were socially battered or removed from society through one form or another, some forms being very unpleasant (being burned at the stake as with Cardinal Bruno, shortly before Descartes' time).

Mathematics (the language which gave the mind adequate descriptions of the material world) and logic (the means by which truth could be established from true principles), Descartes believed, were the keys to obtain knowledge, but paradoxically, geometry (the science of extension) and the new concept of matter as a quantitative stuff gave rise to as many problems as they solved. For example, if everything is extended bodies, then how is the existence of minds explained, for minds don't seem to be bodily at all? How do minds and bodies interact; they don't seem to have anything in common? If bodies are simply extended stuff, then what causes them to move; there is nothing in the concept of an extended bulk that gives it the power of self-movement? (Descartes was absolutely amazed with magnets and could not give any reasonable explanation of their properties.) Further, how is it that we see the quantitative stuff of the world, the atoms, as having qualities such as colors; is the atomic world apart from our experience devoid of these qualities and the beauty that they bring?

So, Descartes' mission was to save the new sciences with all their problems from the Church and, in fact, themselves. Quantifying the world by conceiving it to consist of atoms enabled science to get on the right track experimentally, but as with any radical solution, the solution or cure began to look as bad as the disease. How so?

The problem of saving the sciences was compounded for Descartes. He was also a devoutly religious person, and he was not about to let God be cast away in the washwater of critical reason. The new sciences could explain a great deal, but not everything, especially how persons ought to live together.

Descartes situation was this. He had to save the fledgling sciences from the purges of the Church. But, he had to do so in a way that would give the Church an important role to play in the lives of persons. Whatever solution he would come up with had to reconcile or nullify the differences between the sciences and religion. Moreover, in doing so, he had to explain satisfactorily the relationship between quantitative bodies (atoms, which do not move on their own, which lack freedom either individually or conjunctively, and which do not admit of aesthetic qualities --properties such as colors, smoothness, and etc.) and minds (which are non-quantitative, involve freedom and error individually and socially, and contain ideas which have qualities). Descartes could not rely directly on revealed knowledge or Scripture for the solution, for that would return man to the dark ages of passive knowledge. Nor could he rely solely on mathematics or geometry in its pure form, for, although it would enable man to obtain knowledge of the quantitative world, as an explanatory principle, it did not appear to be complete; it could not explain the existence of minds and their ideas (especially purposes), qualities, or even the movement of bodies themselves.

Descartes' quandary is not unlike the situation many of us find ourselves in today. Our physicists tell us that our world is very much a mathematical machine devoid of any purpose or qualities. It is a world of quanta, sub-atomic bundles of extended energy with indefinite boundaries. They contain no qualitative properties in themselves, but can cause qualities to appear in our minds through the senses. They are strictly determinate, save for a principle of indeterminacy that borders on pure randomness. On the other hand, our society emphasizes personal autonomy (choices towards ends or purposes), the responsibility which free choice involves, and appreciation of the beauty of our surroundings. Moreover, if humans are fundamentally mechanical, biological systems whose actions are determined by physical laws, then the concepts of freedom of will and moral responsibility (attributes which belong to the mental nature of the person in that we have beliefs that we are free) cannot exist; in fact, even the presupposition that there are minds or persons is brought into critical question. Persons are merely passive (unexplained) ghosts in atomic machines. Finally, since many of us, like Descartes, believe that God exists, a new science must be compatible with whatever conception of God we may have. As we may see, Descartes' problem is of great interest to us, for it is very much like the one we find ourselves up against today.

2. Knowledge consists of ideas which are absolutely certain, which cannot be doubted; the way to knowledge is through a method of doubt.

If a solution is to be gained, Descartes thought, it must come from the powers of the human intellect, the rational power to discover truth. The method of subscribing to revealed knowledge of the Scriptures would not do, for the obvious reasons that the new sciences were proving those Scriptures to be wanting. But, a method of induction used by scientists would not do either. Why? Because that method only ends up with probably true hypotheses, not absolutely true hypotheses. For example, if we were to draw 99 red balls from a box containing 100 balls, we could not conclude with certainty that, "All the balls in the box are red." At best, we could say that there is a reasonable chance (about 1 in 100 actually) that the hypothesis is true. No data taken from experiences of the world can give the certainty attributed to knowledge. Descartes wanted to know the TRUTH about matters, and whatever was the truth, he surmised, was not subject to probability; if the answer could change at another time, then it could become false. Descartes wanted something which was TRUE ALL OF THE TIME; let us call something that is true all the time a necessary truth. It is not possible that a necessary truth be false. Only such a truth could be called knowledge; all else would only be probably the case (opinion).

Descartes came to the conclusion that he needed a new method capable of giving him absolutely certain truth. For, once the truth was discovered, then logic would ensure that whatever propositions followed through valid deduction from the absolutely true premise(s) (THE TRUTH) would themselves be absolutely true. Descartes held that true conclusions could only follow from true premises if reason were applied correctly. Let me put his belief another way in cyber-talk. If reason could discover the CD-ROM disk that contained the truth, then any properly operating DOS system (reason) would always produce the exact same true answers when the disk was run. He had to have a method that would let him find that CD-ROM disk and then let reason (each person's DOS system) play it in the person's mind so that he, also, would have absolute truth. Given that reason was a universal DOS system and that the CD-ROM disk contained the truth, every person could be privy to the truth about the world.

The method he came up with reflects his genius. He said to himself (I am paraphrasing Descartes here) something to the effect, "If truth or knowledge is absolutely certain, then there is NOTHING ABOUT IT THAT CAN BE CAST INTO DOUBT. That's it! My method will be to doubt any and everything which is said to be knowledge. Whatever stands up to my method (if there is anything of that nature), whatever is indubitable, will be absolutely certain. I shall doubt the truth of every belief, and if there is the slightest bit of ambiguity or fuzziness there, I shall cast out that belief. An absolutely true proposition or idea can have no counter-examples. I shall examine all ideas and principles, and if there are any possible counter-examples or relevant ambiguities, then that will be sufficient to cast them out. Whatever is left must be indubitable, absolutely certain." Descartes, needless to say, called his method, the method of doubt. Again, in cyber-talk, Descartes was going to run a clean-up program on his hard-disk; any data on the disk that looked like it could fall through or crash would be discarded. What he would end up with would be a perfect file of data which, when run on anyone else's' machine (logical mind) would reproduce itself exactly. Scientific truth would not only be possible, it would be a fact discoverable by reason.

Well, Descartes had his method, but where or what was his lab and what were the subjects in it? The answer was straightforward. Descartes would apply his method to whatever it was he claimed to know, to all the ideas in his mind. Since he was up to date on what most everyone else believed, he merely had to retreat to a quiet place, sit down and reflect upon what was in his mind. His mind constituted the laboratory and the ideas in his mind were the experimental subjects. So, Descartes took a break, went off to a mountain retreat, sat back beside a warm fire and performed his experiments. He began to doubt the truth of the ideas in his mind --and there were plenty of them.

Since we are also good scientists, we know that any worthwhile experiment can be reproduced by other experimenters. And that's just what we are going to do now; we are going to repeat Descartes' experiment. After all, great experiments need corroboration and there need be no reason why we should not test to see if we do not obtain the same results. Let us proceed.

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