| History of Science Rene Descartes 1596-1650 - Francis Bacon defined the polemical and far reaching goals of the new science. Rene Descartes established the mathematical method and rational character of the new enterprise. One of the most important philosophical essays produced in the modern period was Descartes Discourse on Method. Written in the vernacular (everyday language), the work defined a new approach to the study of science. The following passages are meant to suggest the character of Descartes thought. Read through them and think about their implications. I have supplied some comments and questions throughout this document. - From the Discourse on Method If this discourse seems too long to be read at one sitting, it may be divided into six parts. In the first will be found various thoughts on the sciences; in the second, the principal rules of the method the author has used; in the third, some moral rules derived from this method; in the fourth, his proofs of the existence of God and of the human soul which form the basis of his philosophy; in the fifth are treated some questions of physics, especially the explanation of the heartbeat and of some difficulties in medicine, as well as the difference between the souls of men and animals; and in the last, some prerequisites for further advances in the study of nature, as well as the author's reasons for writing this work. [Note the tone. What does this introduction tell you about Descartes's way of approaching problems?] Part One: Some Thoughts on the Sciences Good sense is mankinds most equitably divided endowment, for everyone thinks that he is so abundantly provided with it that even those most difficult to please in other ways do not usually want more than they have of this. As it is not likely that everyone is mistaken, this evidence shows that the ability to judge correctly, and to distinguish the true from the false - which is really what is meant by good sense or reason - is the same by nature in all men; and that differences of opinion are not due to differences in intelligence, but merely to the fact that we use different approaches and consider different things. For it is not enough to have a good mind: one must use it well. The greatest souls are capable of the greatest vices as well as of the greatest virtues; and those who walk slowly can, if they follow the right path go much further than those who run rapidly in the wrong direction. [What is Descartes doing in this opening? That is a complex question. To answer it divide the statement up into component parts. You might think of it this way: everything that Descartes is saying here is an answer to some kind of question. Discover the questions and you understand what he is doing. For instance, Descartes begins by talking about "good sense". What does he say about the distribution of "good sense?" How does he account for differences of opinions among men? What role does he think that the proper method has in finding the truth? How would you characterize the way in which Descartes thinks that the mind should approach problems?] It is true that while I did nothing but observe the customs of other men, I found nothing there to satisfy me, and I noted just about as much difference of opinion as I had previously remarked among philosophers. The greatest profit to me was, therefore, that I became acquainted with customs generally approved and accepted by other great peoples that would appear extravagant and ridiculous among ourselves, and so I learned not to believe too firmly what I learned only from example and custom. Also I gradually freed myself from many errors which could obscure the light of nature and make us less capable of correct reasoning. But after spending several years in thus studying the book of nature and acquiring experience, I eventually reached the decision to study my own self, and to employ all my abilities to try to choose the right path. This produced much better results in my case, I think, than would have been produced if I had never left my books and my country. [Again, what is Descartes saying here? How does he go about studying? Where does he look first? What does he discover? Where does he finally turn his gaze? What is the final object that he concentrates on for his object of study?] Part Two The Principal Rules of Method I had discovered in college that one cannot imagine anything so strange and unbelievable but that it has been upheld by some philosopher; and in my travels I had found that those who held opinions contrary to ours were neither barbarians nor savages, but that many of them were at least as reasonable as ourselves. I had considered how the same man, with the same capacity for reason, becomes different as a result of being brought up among Frenchmen or Germans than he would be if he had been brought up among Chinese or cannibals; and how, in our fashions the thing which pleased us ten years ago and perhaps will release us again ten years in the future, now seems extravagant and ridiculous; and I felt in all these ways we are much more greatly influenced by custom and example than by any certain knowledge. Faced with this divergence of opinion, I could not accept the testimony of the majority, for I thought it worthless as a proof of anything somewhat difficult to discover, since it is much more likely that a single man will have discovered it than a whole people. Nor, on the other hand, could I select anyone whose opinions seemed to me to be preferable to those of others, and I was thus constrained to embark on the investigations for myself. [What does Descartes have to say about what he learned at college? What role does custom play in bringing us a knowledge of truth? What about his opinion of the judgments of single men? How is he left to find truth?] Nevertheless, like a man who walks alone in the darkness, I resolved to go so slowly and circumspectly that if I did not get ahead very rapidly I was at least safe from falling. Also, I did not want to reject all the opinions which had slipped irrationally into my consciousness since birth, until I had first spent enough time planning how to accomplish the task which I was then undertaking, and seeking the true method of obtaining knowledge of everything which my mind was capable of understanding. Among the branches of philosophy, I had, when younger, studied logic, and among those mathematics, geometrical analysis, and algebra; three arts or sciences which should contribute something to my design....I thought that instead of the great number of precepts of which logic is composed, I would have enough with the four following ones, provided I made a firm and unalterable resolution not to violate them even in a single instance: The first rule was never to accept anything as true unless I recognized it to be evidently such; that is , carefully to avoid precipitation and pre-judgment, and to include nothing in my conclusions unless it presented itself so clearly and distinctly to my mind that there was no occasion to doubt it. The second was to divide each of the difficulties which I encountered into as many parts as possible, and as might be required for easier solution. The third was to think in an orderly fashion, beginning with the things which were simplest and easiest to understand, and gradually by degrees reaching toward more complex knowledge, even treating as though ordered materials which were not necessarily so. The last was always to make enumerations so complete, and reviews so general, that I would be certain that nothing was omitted. The exact observation of the few precepts which I had chosen gave me such facility in clarifying all the issues in these two science (algebra and geometrical analysis) that it took only two or three months to examine them. I began with the most simple and general, and each truth that I found was a rule which helped me to find others, so that I not only solved many problems which I had previously judged very difficult,. but also it seemed to me that toward the end I could determine to what extent a still-unsolved problem could be solved, and what procedures should be used in solving it. Part Four: Proofs of the Existence of God and of the Human Soul I do not know whether I ought to touch upon my first meditations here, for they are so metaphysical and out of the ordinary that they might not be interesting to most people. Nevertheless, in order to show whether my fundamental notions are sufficiently sound, I find myself more or less constrained to speak of them. I had noticed for a long time that in practice it is sometimes necessary to follow opinions which we know to be very uncertain, just as though they were indubitable, as I stated before; but inasmuch as I desired to devote myself wholly to the search for truth, I thought that I should take a course precisely contrary, and reject as absolutely false anything of which I could have the least doubt, in order to see whether anything would be left after this procedure which could be called wholly certain. Thus, as our senses deceive us at times, I was ready to suppose that nothing was at all the way our senses represented them to be. As there are men who make mistakes in reasoning even on the simplest topics in geometry, I judged that I was as liable to error as any other, and rejected as false all the reasoning which I had previously accepted as valid demonstration. Finally, as the same precepts which we have when awake may come to us when asleep without their being true, I decided to suppose that nothing that had ever entered my mind was more real than the illusions of my dreams. But I soon noticed that while I thus wished to think everything false, it was necessarily true that I who thought so was something. Since this truth, I THINK, THEREFORE I AM, was so firm and assured that all the most extravagant suppositions of the skeptics were unable to shake it, I judged that I could safely accept it as the first principle of the philosophy I was seeking. I then examined closely what I was, and saw that I could imagine that I had no body, and that there was no world nor any place I occupied, but that I could not imagine for a moment that I did not exist. On the contrary, from the very fact that I doubted the truth of other things, it followed very evidently and very certainly that I existed. On the other had, if I had ceased to think while all the rest of what I had ever imagined remained true, I would have had no reason to believe that I existed; therefore I concluded that I was a substance whose whole essence or nature was only to think, and which, to exist, has no need of space nor of any material thing. Thus it follows that this ego, this soul, by which I am what I am, is entirely distinct from the body and is easier to know than the latter, and that even if the body were not, the soul would not cease to be all that it now is. [This passage contains one of the most famous philosophical statements of the modern period: "I think, therefore I am." What Descartes is looking for here is an "absolute ground zero" on which to build his quest for knowledge. Reread the passage and look at the steps that he takes. What does he have to say about "reason"; or "sense data?" What is the relationship of mind and matter in Descartes' system?] Part Six: Some Prerequisites for Further Advances in the Study of Nature I noticed that experimentation becomes more necessary in proportion as we advance knowledge. In beginning an investigation it is better to restrict ourselves to our usual experiences, while we cannot ignore if we pay any attention to them at all, than to seek rarer and more abstruse experiences. The reason for this is that these latter are often deceiving when the causes of the more common phenomena are still unknown, as the circumstances on which they depend are almost always so particular and so minute that it is very difficult to discover them. My own procedure has been the following: I first tried to discover the general principles or first causes of all that exists or could exist in the world, without taking any causes into consideration but God as creator, and without using any evidence save certain indications of the truth which we find in our own minds. After that I examined what were the first and commonest effects which could be deduced from these causes; and it seems to me that by this procedure I discovered skies, stars, an earth, and even, on the earth, water, air, fire, minerals, and several other things which are the commonest of all and the most simple, and in consequence the easiest to understand. Then, when I wanted to descend to particulars, it seemed to me that there were so many different kinds that I believed it impossible for the human mind to distinguish the forms or species of objects found on earth from an infinity of others which might have been there if God so willed. It thus appeared impossible to proceed further deductively, and if we were to understand and make use of things, we would have to discover causes by their effects, and make use of many experiments. In consequence, reviewing in my mind all the objects which had ever been presented to my senses, I believe I can say that I have never noticed anything which I could not explain easily enough by the principles I had found. But I must also admit that the powers of nature are so ample and vast, and that these principles are so simple and general, that I hardly ever observed a particular effect without immediately recognizing several ways in which it could be deduced. My greatest difficulty usually is to find which of these is the true explanation, and to do this I know no other way than to seek several experiments such that their outcomes would be different according to the choice of hypotheses. | |
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