In Descartes’s Writings

Descartes first wrote the phrase in French in his 1637 Discourse on the Method. He referred to it in Latin without explicitly stating the familiar form of the phrase in his 1641 Meditations on First Philosophy. The earliest written record of the phrase in Latin is in his 1644 Principles of Philosophy, where, in a margin note, he provides a clear explanation of his intent. Fuller forms of the phrase are attributable to other authors.

Discourse on the Method

The phrase first appeared (in French) in Descartes’s 1637 Discourse on the Method in the first paragraph of its fourth part:

• French: “… Ainsi, à cause que nos sens nous trompent quelquefois, je voulus supposer qu’il n’y avoit aucune chose qui fût telle qu’ils nous la font imaginer; et parce qu’il y a des hommes qui se méprennent en raisonnant, même touchant les plus simples matières de géométrie, et y font des paralogismes, jugeant que j’étois sujet à faillir autant qu’aucun autre, je rejetai comme fausses toutes les raisons que j’avois prises auparavant pour démonstrations; et enfin, considérant que toutes les mêmes pensées que nous avons étant éveillés nous peuvent aussi venir quand nous dormons, sans qu’il y en ait aucune pour lors qui soit vraie, je me résolus de feindre que toutes les choses qui m’étoient jamais entrées en l’esprit n’étoient non plus vraies que les illusions de mes songes. Mais aussitôt après je pris garde que, pendant que je voulois ainsi penser que tout étoit faux, il falloit nécessairement que moi qui le pensois fusse quelque chose; et remarquant que cette vérité, je pense, donc je suis, étoit si ferme et si assurée, que toutes les plus extravagantes suppositions des sceptiques n’étoient pas capables de l’ébranler, je jugeai que je pouvois la recevoir sans scrupule pour le premier principe de la philosophie que je cherchois.”
• English: “… Accordingly, seeing that our senses sometimes deceive us, I was willing to suppose that there existed nothing really such as they presented to us; and because some men err in reasoning, and fall into paralogisms, even on the simplest matters of geometry, I, convinced that I was as open to error as any other, rejected as false all the reasonings I had hitherto taken for demonstrations; and finally, when I considered that the very same thoughts (presentations) which we experience when awake may also be experienced when we are asleep, while there is at that time not one of them true, I supposed that all the objects (presentations) that had ever entered into my mind when awake, had in them no more truth than the illusions of my dreams. But immediately upon this I observed that, whilst I thus wished to think that all was false, it was absolutely necessary that I, who thus thought, should be somewhat; and as I observed that this truth, I think, therefore I am,[c] was so certain and of such evidence that no ground of doubt, however extravagant, could be alleged by the sceptics capable of shaking it, I concluded that I might, without scruple, accept it as the first principle of the philosophy of which I was in search.”

Luc Paquin

Cogito ergo sum is a Latin philosophical proposition by René Descartes usually translated into English as “I think, therefore I am”. The phrase originally appeared in French as “je pense, donc je suis” in his Discourse on the Method, so as to reach a wider audience than Latin would have allowed. It appeared in Latin in his later Principles of Philosophy. As Descartes explained, “[W]e cannot doubt of our existence while we doubt… .” A fuller form, dubito, ergo cogito, ergo sum (“I doubt, therefore I think, therefore I am”), aptly captures Descartes’ intent.

This proposition became a fundamental element of Western philosophy, as it purported to form a secure foundation for knowledge in the face of radical doubt. While other knowledge could be a figment of imagination, deception, or mistake, Descartes asserted that the very act of doubting one’s own existence served – at minimum – as proof of the reality of one’s own mind; there must be a thinking entity – in this case the self – for there to be a thought.

Luc Paquin

I Think, Therefore I Am

While methodic doubt has a nature, one need not hold that knowledge is impossible in order to apply the method of doubt. Indeed, Descartes’ attempt to apply the method of doubt to the existence of himself spawned the proof of his famous saying, “Cogito ergo sum” (I think, therefore I am). That is, Descartes tried to doubt his own existence, but found that even his doubting showed that he existed, since he could not doubt if he did not exist.

Criticisms

Cartesian skepticism advocates the doubting of all things which cannot be justified through logic. Some have claimed that the corresponding philosophical proposition fails the criterion of falsifiability that is associated with empirical theory.

Incontrovertible Evidence

Incontrovertible evidence is a colloquial term for evidence introduced to prove a fact that is supposed to be so conclusive that there can be no other truth as to the matter; evidence so strong it overpowers contrary evidence, directing a fact-finder to a specific and certain conclusion.

Luc Paquin

Descartes’ Method

René Descartes, the originator of Cartesian doubt, put all beliefs, ideas, thoughts, and matter in doubt. He showed that his grounds, or reasoning, for any knowledge could just as well be false. Sensory experience, the primary mode of knowledge, is often erroneous and therefore must be doubted. For instance, what one is seeing may very well be a hallucination. There is nothing that proves it cannot be. In short, if there is any way a belief can be disproved, then its grounds are insufficient. From this, Descartes proposed two arguments, the dream and the demon.

The Dream Argument

Descartes, knowing that the context of our dreams, while possibly unbelievable, are often lifelike, hypothesized that humans can only believe that they are awake. There are no sufficient grounds by which to distinguish a dream experience from a waking experience. For instance, subject a sits at the computer, typing this article. Just as much evidence exists to indicate that the act of composing this article is reality, as there is evidence to demonstrate the opposite. Descartes conceded that we live in a world that can create such ideas as dreams. However, by the end of The Meditations, he concludes that we can distinguish dream from reality at least in retrospect.

The Evil Demon

Descartes reasoned that our very own experience may very well be controlled by an evil demon of sorts. This genius is as clever and deceitful as he is powerful. He could have created a superficial world that we may think we live in.

In Meditation I, Descartes stated that if one were mad, even briefly, the insanity might have driven man into believing that what we thought was true could be merely our minds deceiving us. He also stated that there could be ‘some malicious, powerful, cunning demon’ that had deceived us, preventing us from judging correctly.

Descartes argued that all his senses were lying and since your senses can easily fool you, his idea of an infinitely powerful being must be true as that idea could have only been put there by an infinitely powerful being which would have no reason to be deceitful to him.

Luc Paquin

Cartesian doubt is a form of methodological skepticism or scepticism associated with the writings and methodology of René Descartes (1596-1650). Cartesian doubt is also known as Cartesian skepticism, methodic doubt, methodological skepticism, Universal Doubt, or hyperbolic doubt.

Cartesian doubt is a systematic process of being skeptical about (or doubting) the truth of one’s beliefs, which has become a characteristic method in philosophy. This method of doubt was largely popularized in Western philosophy by René Descartes, who sought to doubt the truth of all his beliefs in order to determine which beliefs he could be certain were true.

Methodological skepticism is distinguished from philosophical skepticism in that methodological skepticism is an approach that subjects all knowledge claims to scrutiny with the goal of sorting out true from false claims, whereas philosophical skepticism is an approach that questions the possibility of pure knowledge.

Characteristics

Cartesian doubt is methodological. Its purpose is to use doubt as a route to certain knowledge by finding those things which could not be doubted. The fallibility of sense data in particular is a subject of Cartesian doubt.

There are several interpretations as to the objective of Descartes’ skepticism. Prominent among these is a foundationalist account which claims that Descartes’ skepticism is aimed at eliminating all belief which it is possible to doubt, thus leaving Descartes with only basic beliefs (also known as foundational beliefs). From these indubitable basic beliefs, Descartes then attempts to derive further knowledge. It’s an archetypal and significant example that epitomizes the Continental Rational schools of philosophy.

Technique

Descartes’ Method

• 1. Accepting only information you know to be true
• 2. Breaking down these truths into smaller units
• 3. Solving the simple problems first
• 4. Making complete lists of further problems

Is also known as hyperbolic doubt or having the tendency to doubt, since it is an extreme or exaggerated form of doubt. (Knowledge in the Cartesian sense means to know something beyond not merely all reasonable, but all possible, doubt.) In his Meditations on First Philosophy (1641), Descartes resolved to systematically doubt that any of his beliefs were true, in order to build, from the ground up, a belief system consisting of only certainly true beliefs. Consider Descartes’ opening lines of the Meditations:

• Several years have now elapsed since I first became aware that I had accepted, even from my youth, many false opinions for true, and that consequently what I afterward based on such principles was highly doubtful; and from that time I was convinced of the necessity of undertaking once in my life to rid myself of all the opinions I had adopted, and of commencing anew the work of building from the foundation…

  – René Descartes , Meditation I, 1641

Luc Paquin

Cartesianism is the name given to the philosophical doctrine (or school) of René Descartes. Descartes is often regarded as the first thinker to emphasize the use of reason to develop the natural sciences. For him, the philosophy was a thinking system that embodied all knowledge, and expressed it in this way:

Cartesians view the mind as being wholly separate from the corporeal body. Sensation and the perception of reality are thought to be the source of untruth and illusions, with the only reliable truths to be had in the existence of a metaphysical mind. Such a mind can perhaps interact with a physical body, but it does not exist in the body, nor even in the same physical plane as the body.

In general, Cartesian thought divides the world into three areas of existence:

• That inhabited by the physical body (matter),
• That inhabited by the mind, and
• That inhabited by God.

Geographical Dispersal

In The Netherlands, where Descartes had lived for a long time, Cartesianism was a doctrine popular mainly among university professors and lecturers. In Germany the influence of this doctrine was not relevant and followers of Cartesianism in the German-speaking border regions between these countries (e.g., the iatromathematician Yvo Gaukes from East Frisia) frequently chose to publish their works in The Netherlands. In France, it was very popular, and gained influence also among Jansenists such as Antoine Arnauld, though there also, as in Italy, it became opposed by the Church. In Italy, the doctrine failed to make inroads, probably since Descartes’ works were placed on the Index Librorum Prohibitorum in 1663.

In England, because of religious and other reasons, Cartesianism was not widely accepted. Though Henry More was initially attracted to the doctrine, his own changing attitudes toward Descartes mirrored those of the country: “quick acceptance, serious examination with accumulating ambivalence, final rejection.”

Notable Cartesians

• Antoine Arnauld
• Balthasar Bekker
• Johannes Clauberg
• Michelangelo Fardella
• Antoine Le Grand
• Adriaan Hereboord
• Nicolas Malebranche
• François Poullain de la Barre
• Edmond Pourchot
• Pierre-Sylvain Régis
• Henricus Regius
• Jacques Rohault
• Christopher Wittich

Luc Paquin

Writings

• 1618. Musicae Compendium. A treatise on music theory and the aesthetics of music written for Descartes’ early collaborator, Isaac Beeckman (first posthumous edition 1650).
• 1626-1628. Regulae ad directionem ingenii (Rules for the Direction of the Mind). Incomplete. First published posthumously in Dutch translation in 1684 and in the original Latin at Amsterdam in 1701 (R. Des-Cartes Opuscula Posthuma Physica et Mathematica). The best critical edition, which includes the Dutch translation of 1684, is edited by Giovanni Crapulli (The Hague: Martinus Nijhoff, 1966).
• 1630-1631. La recherche de la vérité par la lumière naturelle (The Search for Truth) unfinished dialogue published in 1701.
• 1630-1633. Le Monde (The World) and L’Homme (Man). Descartes’ first systematic presentation of his natural philosophy. Man was published posthumously in Latin translation in 1662; and The World posthumously in 1664.
• 1637. Discours de la méthode (Discourse on the Method). An introduction to the Essais, which include the Dioptrique, the Météores and the Géométrie.
• 1637. La Géométrie (Geometry). Descartes’ major work in mathematics. There is an English translation by Michael Mahoney (New York: Dover, 1979).
• 1641. Meditationes de prima philosophia (Meditations on First Philosophy), also known as Metaphysical Meditations. In Latin; a French translation, probably done without Descartes’ supervision, was published in 1647. Includes six Objections and Replies. A second edition, published the following year, included an additional objection and reply, and a Letter to Dinet.
• 1644. Principia philosophiae (Principles of Philosophy), a Latin textbook at first intended by Descartes to replace the Aristotelian textbooks then used in universities. A French translation, Principes de philosophie by Claude Picot, under the supervision of Descartes, appeared in 1647 with a letter-preface to Princess Elisabeth of Bohemia.
• 1647. Notae in programma (Comments on a Certain Broadsheet). A reply to Descartes’ one-time disciple Henricus Regius.
• 1648. La description du corps humaine (The Description of the Human Body). Published posthumously by Clerselier in 1667.
• 1648. Responsiones Renati Des Cartes… (Conversation with Burman). Notes on a Q&A session between Descartes and Frans Burman on 16 April 1648. Rediscovered in 1895 and published for the first time in 1896. An annotated bilingual edition (Latin with French translation), edited by Jean-Marie Beyssade, was published in 1981 (Paris: PUF).
• 1649. Les passions de l’âme (Passions of the Soul). Dedicated to Princess Elisabeth of the Palatinate.
• 1657. Correspondance. Published by Descartes’ literary executor Claude Clerselier. The third edition, in 1667, was the most complete; Clerselier omitted, however, much of the material pertaining to mathematics.

In January 2010, a previously unknown letter from Descartes, dated 27 May 1641, was found by the Dutch philosopher Erik-Jan Bos when browsing through Google. Bos found the letter mentioned in a summary of autographs kept by Haverford College in Haverford, Pennsylvania. The College was unaware that the letter had never been published. This was the third letter by Descartes found in the last 25 years.

Luc Paquin