The Doubt to End All Doubt

It was the passion and declared goal of Descartes to put an end to the pervasive skepticism and uncertainty of the age. As he himself was troubled rather gravely by all sorts of doubts, he could embark on the removal of the general skepticism as a personal quest. He tackled the problem not by producing defenses for all the doubtful opinions that were under attack, but, on the contrary, by intensifying the general doubt to its ultimate extreme. Like a dentist who first cleans away every trace of decay from a diseased tooth before filling in new material, Descartes resolved to doubt absolutely everything that could possibly be doubted--in the hope of thereby finding something that was beyond doubt. Whatever he would find would be the basis for a new body of solid knowledge. His plan, in other words, was to doubt his way to a new certainty.
Descartes received a first-rate education at the famous Jesuit school of La Fleche in France, before leaving his native country to engage in extensive traveling and gentlemen-soldiering in Holland and Germany. After some years he returned to Paris for a short time, but thereafter moved to Holland to live the quiet life of a scholar. Taking advantage of the possibilities of the emerging Capitalist economy, he sold his inherited feudal rights and titles and invested the proceeds in stocks; this allowed him to live comfortably on dividends and interest. Over the years he made important scientific contributions to such fields as optometry, mechanics, and analytic geometry. (The "Cartesian coordinates," for example, are his invention.) He became most famous, however, for his philosophical writings. In them he laid the groundwork for all the analyses and theories that were to occupy European philosophers for the next two-hundred years and beyond.
In 1633 he was about to publish a scientific work called The World, in which he defended, among other things, the heliocentric theory of Copernicus. At the last minute he heard that Galileo was arrested by the Holy Inquisition for defending the same theory. As Descartes throughout his life tried to avoid such dangerous conflicts with the Catholic Church, he prevented the publication of his book. In 1637 he published his Discourse on Method, in which for the first time he presented his program of radical doubt. This program, too, raised the suspicion of church officials. In response Descartes published, in 1641, his Meditations on First Philosophy, in which he defended his program of doubt by showing that such an undertaking would not necessarily be in conflict with Catholic teachings. The Meditations, although a slim volume, became an all-time classic. In a sense it is the beginning of modern philosophy. And its center is the definition of the self as the one thing in the world that cannot be doubted in any way.
The book starts out with Descartes’ description of his intention, namely to rid his mind of all dubious and uncertain opinions—in order to have a sound foundation for his future scientific research:
I have not just now learned that, from my earliest years, I have received many false opinions as true, and that what I have since based on such unstable principles could not but be very doubtful and uncertain. And ever since I have realized that I would have to undertake seriously once in my life to be rid of all the opinions I have previously received into my credence, and start all over again from the foundations, if I wanted to establish something firm and constant in the sciences. ... So today, quite opportunely for this plan, I have freed my mind of all sorts of cares--fortunately feeling undisturbed by any passions, and having found a secure repose in peaceful solitude. I shall apply myself seriously and freely to the general destruction of all my old opinions.
As can be seen from these introductory remarks, Descartes establishes his program of radical doubt as a decidedly solitary enterprise. He is conducting his philosophical work in deliberate isolation--away from other people, and protected from the disturbances that usually come with practical concerns and emotional involvement. At the beginning of his Discourse On Method he had been similarly concerned with shielding himself from inner and outer disturbances: "... I was caught by the onset of winter.
There was no conversation to distract me, and being untroubled by any cares or passions, I remained all day alone in a warm room. There I had plenty of leisure to examine my ideas." Lack of company, lack of disquieting emotions, and the absence of physical discomfort are the conditions that he considered ideal for his philosophical undertaking--quite in contrast to the conditions under which a thinker like Socrates would do his work. Socrates pursued his philosophical investigations in dialogue with other people, surrounded by spectators and listeners, in often heated exchanges, and sometimes with much to worry about in terms of his well being and safety. Descartes’ deliberate retreat from passionate and full-fledged involvement in life into deep solitude is more than a personal whim. Even a detail like the quiet of winter is not an accidental feature of the scene of his work: it fits the calm and unemotional way in which this philosopher wished to do his thinking. The pronounced solitude of Descartes’ ivory tower corresponds, as will be seen, perfectly to the concept of self that he was to develop.
Descartes starts his program of radical doubt in a relatively ordinary way, in a way any critical scholar would go about doubting: He suspends his former belief in the teachings of his academic teachers. This in itself, however, would have been nothing new or particularly radical; a good deal of scholarly work at all times consists in doing just that. The philosophically radical part of his program went into effect when Descartes cast doubt on something that ordinarily has to be taken for granted: the testimony of the senses. In his words: "All that I have hitherto received as the most true and assured I have from the senses or by the senses. Now, I have sometimes found that these senses are deceptive; and it is wise never to rely entirely on those who have deceived us once."
This simple dismissal of the trustworthiness of the senses, however, is none too convincing, as Descartes himself realizes. For the very detection of a false testimony of the senses still requires the use of the senses: To see that a distant object is not a tree, for example, but a water pump, one has to get close to the object and take a look at it. It is my eyes that will tell me whether my earlier impression was true or false.
To effectively cast doubt on the truth of all sense perception, Descartes has to come up with a better argument. For this purpose he designs his famous dream argument:
How often it has happened that I dreamed at night that I was by the fire, though I was quite naked in my bed! ... I am reminded of having been deceived by similar illusions while sleeping; and, lingering on this thought, I see so clearly that there is no certain index at all by which wakefulness can be clearly distinguished from sleep, that I am quite amazed and my amazement is such that it is almost capable of persuading me that I am dreaming right now.
While dreaming, in other words, one is usually under the impression that what one is dreaming is real. When I dream that I am sitting in front of the fire place then I take it for granted that I am sitting in front of the fire place, even though I am lying in bed. I usually will not discover my mistake until I wake up. But if I can be so mistaken in dreams that I have had in the past, how can I be sure that I am not dreaming right now? I obviously think that I am sitting here, writing down these words; but how can I prove that I will not wake up in a while and see that this, too, has been but a dream? How can I possibly distinguish waking experiences from dreaming experiences?
The crux of Descartes' Dream Argument is the fact that there is no "index" that indicates whether any given experience is real or a dream. My sitting here and writing this can be a real event, but it can also be a dream. Dreams, after all, can be very clear and vivid--so vivid that they make me sweat or be afraid in the same way real events do. Without an "index" (perhaps something like "C-SPAN" in the lower right corner of my visual field) I simply cannot know for sure whether what I see or feel or hear is real or not. All I can be sure of is that I have an experience--an experience involving the senses of sight, touch, or whatever else may be involved. Consequently I do not know whether these sense impressions are impressions of something that exists out there in the world (a real writing desk, a real pen, etc.), or whether they are figments of my imagination. The world that I perceive around me right now may be real, but it may also be mere appearance, a deception. And even if it seems extremely probable that what I see and touch right now is real, and not a dream, I cannot be entirely certain about it. And absolute certainty is what is at issue here.
Since Descartes' program of radical doubt requires that he doubt not only those things that are obviously dubious, but everything that can be doubted at all, Descartes has to suspend his belief in the reality of the external world--everything which we perceive with our senses. This includes the reality of his own body. Thus, for the time of his philosophical reflections he will assume that the seemingly material world around him is not real, but something like a collection of impressions that an "evil genie" has put in his mind:
I shall assume that the sky, the air, the earth, colors, shapes sounds and all other external things are just illusions and dreams which he [the evil genie] has used to lay traps for my credulity. I shall consider myself to have no hands, no eyes, no flesh, no blood, as not having any senses, yet falsely believing that I have all these things.
Although this assumption can be seen as just a device that Descartes uses in his search for something absolutely certain, the feeling of the unreality of the external world was a very powerful one at the time. Poets and playwrights frequently invoked the images of the world as a mere stage, where people don masks and play out roles, and life as nothing but a fleeting dream. Descartes himself once wrote in a letter to a friend: "So far, I have been a spectator in this theater which is the world, but I am now about to mount the stage, and I come forward masked." The general insecurity with regard to the reality of everything was so pervasive that Descartes' philosophical supposition of the illusory nature of the external world was by no means crazily fantastic or exotic for his readers.
Assuming then that the entire external world, including one's body, is a dreamlike illusion, is there anything at all left that cannot be doubted? The fact that "I am, I exist" is Descartes' answer. And this, in a nutshell, is how he arrived at that conclusion: I can doubt the existence of the external world, and I can doubt the existence of what appears to be my body. But when I try to also doubt the existence of my inner self, my thinking, then I find that I am still there--as a doubting mind. And if I try to doubt the existence of this doubting mind, then I still find the activity of my doubting. And no matter how hard I try to doubt this doubting, I cannot help but find the process of doubting. My doubting is the thing that in the end I cannot doubt. Doubting, however, is thinking, and the existence of thinking implies the existence of a thinker. Hence Descartes' famous conclusion: "I think, therefore I am"("Cogito, ergo sum" in the Latin in which he wrote).
After establishing that the exists, Descartes lays out the answer to the question as to what he is:
I find here that thought is an attribute that belongs to me; it alone cannot be separated from me. I am, I exist--that is certain; but for how long? As long as I think. For it may happen that, if I stopped thinking altogether, I would at the same time altogether cease being. I am now admitting nothing that would not be necessarily true. Thus I am, speaking precisely, only a thinking thing; that is to say, a mind, an understanding, or a reason, which are terms whose meaning was previously unknown to me. In other words: I am a real thing and really existent; but what thing? I have already said it: a thing that thinks.