The Latin , usually translated into English as "I think, therefore I am", is the "first principle" of the philosophy of the French scientist and philosopher René Descartes. He originally published it in French as , in his 1637 Discourse on the Method, so as to reach a wider audience than Latin would have allowed. It later appeared in Latin in his Principles of Philosophy, and a similar phrase () also featured prominently in his Meditations on First Philosophy. The dictum is also sometimes referred to as the cogito. As Descartes explained in a margin note, "we cannot doubt of our existence while we doubt." In the posthumously published The Search for Truth by Natural Light, he expanded it to ("I doubt, therefore I am—or what is the same—I think, therefore I am.").. Antoine Léonard Thomas, in a 1765 essay in honor of Descartes, wrote in summary: ("I doubt, therefore I think, therefore I am.").
Descartes's statement became a fundamental element of Western philosophy, as it purported to provide a certain 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.
One critique of the dictum, first suggested by Pierre Gassendi, is that it presupposes that there is an "I" which must be doing the thinking. According to this line of criticism, the most that Descartes was entitled to say was that "thinking is occurring", not that "I am thinking". from Stanford Encyclopedia of Philosophy
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 (see below), he provides a clear explanation of his intent: "[W]e cannot doubt of our existence while we doubt". 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:
Meditations on First Philosophy In 1641, Descartes published (in Latin) Meditations on first philosophy in which he referred to the proposition, though not explicitly as "cogito, ergo sum" in Meditation II:
In Response to an Objection from Marin Mersenne, he wrote "cogito, ergo sum” in an extended form and, again, prefaced with ‘ego’:
Principles of Philosophy In 1644, Descartes published (in Latin) his Principles of Philosophy which begins (That in order to seek truth, it is necessary once in the course of our life, to doubt, as far as possible, of all things.) The phrase "ego cogito, ergo sum" appears in Part 1, article 7: Descartes's margin note for the above paragraph is:
The Search for Truth by Natural Light Descartes, in a lesser-known posthumously published work written ca. 1647, originally in French with the title (The Search for Truth by Natural Light) and later in Latin with the title , provides his only known phrasing of the cogito as and admits that his insight is also expressible as dubito, ergo sum:
"" or ""? Peter J. Markie notes: "Descartes stresses the first person in his premise twice in the Principles and once in his Reply to Mersenne. . . . . (AT VIII, 7; AT VIII, 8; AT VII, 140)" and adds "It is unlikely that Descartes would stress the first person in his premise, if he wanted us to read the premise as 'Thought is taking place' rather than 'I think. Gary Hatfield writes: "[I]n Latin the first-person voice need not be expressed through a separate pronoun, but may be included in the verb form; nonetheless, Descartes used the Latin first-person pronoun more than thirty times in the six Meditations."
Other forms The proposition is sometimes given as . This form was penned by the French literary critic, Antoine Léonard Thomas, in an award-winning 1765 essay in praise of Descartes, where it appeared as "" ('Since I doubt, I think; since I think, I exist'). With rearrangement and compaction, the passage translates to "I doubt, therefore I think, therefore I am," or in Latin, "dubito, ergo cogito, ergo sum." This aptly captures Descartes's intent as expressed in his posthumously published La Recherche de la Vérité par La Lumiere Naturale as noted above: I doubt, therefore I am – or what is the same – I think, therefore I am.
A further expansion, ("…—a thinking thing") extends the cogito with Descartes's statement in the subsequent Meditation, ("I am a thinking [conscious] thing, that is, a being who doubts, affirms, denies, knows a few objects, and is ignorant of many, [who loves, hates,] wills, refuses, who imagines likewise, and perceives"). This has been referred to as "the expanded cogito."
Translation
"I am thinking" vs. "I think" While the Latin cōgitō may be translated rather easily as "I think/ponder/visualize", does not indicate whether the verb form corresponds to the English present simple ("think") or progressive aspect ("is thinking"). Following John Lyons (1982), Vladimir Žegarac notes, "The temptation to use the present simple is said to arise from the lack of progressive forms in Latin and French, and from a misinterpretation of the meaning of cogito as habitual or generic" (cf. gnomic aspect). Also following Lyons, Ann Banfield writes, "In order for the statement on which Descartes's argument depends to represent certain knowledge,… its tense must be a true present—in English, a progressive,… not as 'I think' but as 'I am thinking, in conformity with the general translation of the Latin or French present tense in such nongeneric, nonstative contexts." Or in the words of Simon Blackburn, "Descartes's premise is not 'I think' in the sense of 'I ski', which can be true even if you are not at the moment skiing. It is supposed to be parallel to 'I am skiing'."
The similar translation "I am thinking, therefore I exist" of Descartes's correspondence in French (", ") appears in The Philosophical Writings of Descartes by Cottingham et al. (1988).
The earliest known translation as "I am thinking, therefore I am" is from 1872 by Charles Porterfield Krauth.
Fumitaka Suzuki writes "Taking consideration of Cartesian theory of continuous creation, which theory was developed especially in the Meditations and in the Principles, we would assure that 'I am thinking, therefore I am/exist' is the most appropriate English translation of 'ego cogito, ergo sum'."
"I exist" vs. "I am" Alexis Deodato S. Itao notes that is "literally 'I think, therefore I am'." Others differ: 1) "[A] precise English translation will read as 'I am thinking, therefore I exist'; and 2) "[S]ince Descartes ... emphasized that existence is such an important 'notion,' a better translation is 'I am thinking, therefore I exist.'"
Punctuation Descartes wrote this phrase as such only once, in the posthumously published lesser-known work noted above, The Search for Truth by Natural Light. It appeared there mid-sentence, uncapitalized, and with a comma. (Commas were not used in Classical Latin but were a regular feature of scholastic Latin, the Latin Descartes "had learned in a Jesuit college at La Flèche.") Most modern reference works show it with a comma, but it is often presented without a comma in academic work and in popular usage. In Descartes's Principia Philosophiae, the proposition appears as ego cogito, ergo sum.
Interpretation As put succinctly by Krauth (1872), "That cannot doubt which does not think, and that cannot think which does not exist. I doubt, I think, I exist."
The phrase cogito, ergo sum is not used in Descartes's Meditations on First Philosophy, but the term "the cogito" is used to refer to an argument from it. In the Meditations, Descartes phrases the conclusion of the argument as "that the proposition, I am, I exist, is necessarily true whenever it is put forward by me or conceived in my mind" (Meditation II). George Henry Lewes says Descartes "has told us that [his objective] was to find a starting point from which to reason—to find an irreversible certainty. And where did he find this? In his own consciousness. Doubt as I may, I cannot doubt of my own existence, because my very doubts reveal to me a something which doubts. You may call this an assumption, if you will; I point out the fact as one above and beyond all logic; which logic can neither prove nor disprove; but which must always remain an irreversible certainty, and as such a fitting basis of philosophy."
At the beginning of the second meditation, having reached what he considers to be the ultimate level of doubt—his argument from the existence of a deceiving god—Descartes examines his beliefs to see if any have survived the doubt. In his belief in his own existence, he finds that it is impossible to doubt that he exists. Even if there were a deceiving god (or an evil demon), one's belief in their own existence would be secure, for there is no way one could be deceived unless one existed in order to be deceived.
There are three important notes to keep in mind here. First, he claims only the certainty of his own existence from the first-person point of view — he has not proved the existence of other minds at this point. This is something that has to be thought through by each of us for ourselves, as we follow the course of the meditations. Second, he does not say that his existence is necessary; he says that if he thinks, then necessarily he exists (see the instantiation principle). Third, this proposition "I am, I exist" is held true not based on a deduction (as mentioned above) or on empirical induction but on the clarity and self-evidence of the proposition. Descartes does not use this first certainty, the cogito, as a foundation upon which to build further knowledge; rather, it is the firm ground upon which he can stand as he works to discover further truths.Self, Reason, and Freedom: A New Light on Descartes' Metaphysics Andrea Christofidou; chapter 2 As he puts it:
According to many Descartes specialists, including Étienne Gilson, the goal of Descartes in establishing this first truth is to demonstrate the capacity of his criterion — the immediate clarity and distinctiveness of self-evident propositions — to establish true and justified propositions despite having adopted a method of generalized doubt. As a consequence of this demonstration, Descartes considers science and mathematics to be justified to the extent that their proposals are established on a similarly immediate clarity, distinctiveness, and self-evidence that presents itself to the mind. The originality of Descartes's thinking, therefore, is not so much in expressing the cogito—a feat accomplished by other predecessors, as we shall see—but on using the cogito as demonstrating the most fundamental epistemological principle, that science and mathematics are justified by relying on clarity, distinctiveness, and self-evidence. Baruch Spinoza in "Principia philosophiae cartesianae" at its Prolegomenon identified "cogito ergo sum" the "ego sum cogitans" (I am a thinking being) as the thinking substance with his ontological interpretation.
Predecessors