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{{short description|Philosophical statement made by René Descartes}}
{{Redirect|I think, therefore I am|the R. Dean Taylor album|I Think, Therefore I Am{{!}}''I Think, Therefore I Am''|the Billie Eilish song referencing Descartes's principle|Therefore I Am (song)}}
{{DISPLAYTITLE:<i title="Latin-language text" lang="la">Cogito, ergo sum</i>}}
[[File:Frans Hals - Portret van René Descartes.jpg|thumb|[[René Descartes]], who published the phrase in ''[[Discourse on the Method]]'', in 1637]]
{{Descartes}}
The Latin '''{{lang|la|cogito, ergo sum}}''', usually translated into English as "'''I think, therefore I am'''",{{efn|name="better translation" | Some sources offer "I am thinking, therefore I am" as a better translation. (See [[#Translation|§ Translation]].)}} is the "[[first principle]]" of [[René Descartes]]' philosophy. He originally published it in French as '''{{nowrap|{{lang|fr|je pense}}}}, {{nowrap|{{lang|fr|donc je suis}}}}''' in his 1637 ''[[Discourse on the Method]]'', so as to reach a wider audience than Latin would have allowed.<ref>{{cite book |last=Burns |first=William E. |title=The Scientific Revolution: An Encyclopedia |publisher=ABC-CLIO |year=2001 |isbn=978-0-87436-875-8 |location=Santa Barbara, California |page=84}}</ref> It later appeared in Latin in his ''[[Principles of Philosophy]]'', and a similar phrase ({{Langx|la|Ego sum, ego existo|4=I am, I exist|label=none}}) also featured prominently in his ''[[Meditations on First Philosophy]]''.  The [[dictum]] is also sometimes referred to as '''the cogito'''.<ref>{{Cite web |title=COGITO {{!}} Meaning & Definition for UK English {{!}} Lexico.com |url=https://www.lexico.com/definition/cogito |archive-url=https://web.archive.org/web/20210308153135/https://www.lexico.com/definition/cogito |url-status=dead |archive-date=March 8, 2021 |access-date=2022-07-11 |website=Lexico Dictionaries {{!}} English |language=en}}</ref>  As Descartes explained in a [[Marginalia|margin note]], "we cannot [[doubt]] of our [[existence]] while we doubt." In the posthumously published ''[[The Search for Truth by Natural Light]]'', he expressed this insight as {{lang|la|'''dubito, ergo sum''', vel, quod idem est, cogito, ergo sum}} ("I doubt, therefore I am—or what is the same—I think, therefore I am.").<ref name="AT">{{Citation |title=''Oeuvres de Descartes'' |volume=X |page=535 |year=1901 |editor-last1=Adam |editor-first1=Charles |contribution=La Recherche de la Vérité par La Lumiere Naturale |contribution-url=https://fr.wikisource.org/wiki/Page:Descartes_-_Œuvres,_éd._Adam_et_Tannery,_X.djvu/535 |editor-last2=Tannery |editor-first2=Paul}}.</ref><ref name="Hintikka">{{Cite journal|last=Hintikka|first=Jaakko|date=1962|title=Cogito, Ergo Sum: Inference or Performance?|url=https://www.jstor.org/stable/2183678|journal=The Philosophical Review|volume=71|issue=1|pages=3–32|doi=10.2307/2183678|jstor=2183678|issn=0031-8108|url-access=subscription}}</ref> [[Antoine Léonard Thomas]], in a 1765 essay in honor of Descartes, presented it as {{lang|la|dubito, ergo cogito, ergo sum}} ("I doubt, therefore I think, therefore I am.").{{efn|This expression is often mistakenly attributed to Descartes. (See [[Cogito ergo sum#Other forms|Other forms]].)}}

Descartes's statement became a fundamental element of [[Western philosophy]], as it purported to provide a [[certainty|certain]] [[epistemology|foundation for knowledge]] in the face of [[Epistemological skepticism|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 [[Consciousness|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".<ref>{{cite web |author=Fisher, Saul |date=2005 |title=Pierre Gassendi |url=http://plato.stanford.edu/entries/gassendi/ |accessdate=1 December 2014}} from [[Stanford Encyclopedia of Philosophy]]</ref>

== 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:

{{Verse translation|{{lang|fr|Ainsi, à cause que nos sens nous trompent quelquefois, je voulus supposer qu'il n'y avait 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'étais sujet à faillir autant qu'aucun autre, je rejetai comme fausses toutes les raisons que j'avais 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 raison pour lors qui soit vraie, je me résolus de feindre que toutes les choses qui m'étaient jamais entrées en l'esprit n'étaient non plus vraies que les illusions de mes songes. Mais aussitôt après je pris garde que, pendant que je voulais ainsi penser que tout était faux, il fallait nécessairement que moi qui le pensais fusse quelque chose; Et remarquant que cette vérité, '''''{{nowrap|je pense,}} {{nowrap|donc je suis}}''''',{{efn|name="formatting"}} était si ferme et si assurée, que toutes les plus extravagantes suppositions des Sceptiques n'étaient pas capables de l'ébranler, je jugeai que je pouvais la recevoir sans scrupule pour le premier principe de la Philosophie que je cherchais.|italic=unset}}{{efn|name="formatting2"|Capitalization as in original; spelling updated from [[Middle French]] to [[Modern French]].}}{{efn|1=See original ''Discours'' manuscript [https://gallica.bnf.fr/ark:/12148/btv1b86069594/f37.item.zoom here].}}|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 [[:wiktionary:paralogism|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 something; And as I observed that this truth, '''''{{nowrap|I think,}} {{nowrap|therefore I am}}''''',{{efn|name="formatting"}} 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.{{efn|This translation, by Veitch in 1850,<ref name="Veitch1850">{{cite book | author=Veitch, John | title=Discourse on the Method of Rightly Conducting the Reason, and Seeking Truth in the Sciences, by Descartes | publisher=Sutherland and Knox | year=1850 | location=Edinburgh | pages=74–5 | url = https://archive.org/stream/Descartes1637DiscourseOnTheMethodTrVeitch1850/Descartes%201637%20Discourse%20tr%20Veitch%201850#page/n77/mode/2up/search/Therefore+I+am| author-link=John Veitch (poet) }}</ref> is modified here as follows: Veitch's "I think, hence I am" is changed to the form by which it is currently best known in English, "I think, therefore I am", which appeared in the Haldane and Ross 1911 translation,{{r|Haldane1911|p=100}} and as an isolated attributed phrase previously, e.g., in Sullivan (1794);<ref name=Sullivan1794>{{cite book | author=Richard Joseph Sullivan | title=A View of Nature, in Letters to a Traveller among the Alps, with Reflections on Atheistical Philosophy now exemplified in France | year = 1794 | page=129 | url=https://books.google.com/books?id=1q00AAAAMAAJ&pg=PA129 | publisher=printed for T. Becket | location=London| author-link=Richard Joseph Sullivan }}</ref> in the preceding line, Veitch's "I, who thus thought, should be somewhat" is given here as "… should be something" for clarity (in accord with other translations, e.g., that of Cress<ref name=Cress1986 />); and capitalization was reverted to conform to Descartes's original in French.}}{{efn|The 1637 ''Discours'' was translated to Latin in the 1644 ''Specimina Philosophiae''<ref name="Descartes1644Specimina">{{cite book|author=Descartes, René | title=Specimina philosophiae|publisher=Ludovicus Elzevirius |url=https://archive.org/details/ita-bnc-mag-00001403-001|page=[https://archive.org/details/ita-bnc-mag-00001403-001/page/n68 30] |year=1644}}</ref> but this is not referenced here because of issues raised regarding translation quality.<ref name="Vermeulen2006">{{cite journal|author=Vermeulen, Corinna Lucia|title=René Descartes, ''Specimina philosophiae''. Introduction and Critical Edition|journal=Quaestiones Infinitae|url= https://dspace.library.uu.nl/handle/1874/23451|year=2006|volume=53|hdl=1874/23451|type=Dissertation, Utrecht University}}</ref>}}}}

=== ''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:

{{Verse translation|{{lang|la|hoc pronuntiatum: '''Ego sum, Ego existo''',{{efn|name="formatting3"|''Cogito'' variant highlighted to facilitate comparison; capitalization as in original.}} quoties a me profertur, vel mente concipitur, necessario esse verum.<ref name="Descartes1641">{{Cite book |last=Descartes |first=René |url=https://books.google.com/books?id=R41XAAAAcAAJ |title=Meditationes de prima philosophia, in qua Dei existentia et animae immortalitas demonstratur |date=1641 |publisher=Apud Michaelem Soly |pages=359 |language=la}}</ref>|italic=unset}}|this proposition: '''I am, I exist''',{{efn|name="formatting3"}} whenever it is uttered by me, or conceived by the mind, necessarily is true.{{efn|This combines, for clarity and to retain phrase ordering, the Cress<ref name=Cress1986 /> and Haldane<ref name="Haldane1911">{{cite book|author=Descartes, René | title=The Philosophical Works of Descartes, rendered into English|url=https://archive.org/details/philosophicalwor01desc |others=Translated by Elizabeth S. Haldane and G.R.T. Ross| publisher=Cambridge University Press | year=1911}}</ref>{{rp|150}} translations.}}{{efn|Jaako Hintikka comments that ''ego sum, ego existo'' is the simplest example of an "existentially self-verifying" sentence, i.e., one whose negation verifies itself "when … expressly uttered or otherwise professed"; and that ''ego sum'' is an alternative to ''cogito, ergo sum'' to express "the existential inconsistency of the sentence 'I don't exist' and the existential self-verifiability of 'I exist'".<ref name=Hintikka />}}}}

In Response to an Objection from [[Marin Mersenne]], he wrote "cogito, ergo sum” in an extended form and, again, prefaced with ‘ego’:

{{Verse translation|{{lang|la|Cum advertimus nos esse res cogitantes, prima quædam notio est quæ ex nullo syllogismo concluditur; neque etiam cum quis dicit ‘'''ego cogito, ergo sum, sive existo''',’{{efn|name="formatting3"|''Cogito'' variant highlighted to facilitate comparison; capitalization as in original.}} existentiam ex cogitatione per syllogismum deducit, sed tanquam rem per se notam simplici mentis intuitu agnoscit.{{sfn|Descartes|1641|p=189}}|italic=unset}}|And when we become aware that we are thinking things, this is a primary notion which is not derived by means of any syllogism. When someone says ''''I am thinking, therefore I am, or I exist'''’{{efn|name="formatting3"}} he does not deduce existence from thought by means of a syllogism, but recognizes it as something self-evident by a simple intuition of the mind.<ref>{{Cite book |last1=Cottingham |first1=John |url=https://books.google.com/books?id=Q5P2lFaM8GgC&q=The+Philosophical+Writings+of+DESCARTES+translated+by+JOHN+COTTINGHAM+ROBERTSTOOTHOFF+DUGALD+MURDOCH+%22volume+2%22 |title=The Philosophical Writings of Descartes |last2=Stoothoff |first2=Robert |last3=Murdoch |first3=Dugald |publisher=Cambridge University Press |year=1984 |isbn=978-0-521-28808-8 |pages=71 |language=en}}</ref>}}

=== ''Principles of Philosophy'' ===
In 1644, Descartes published (in Latin) his ''[[Principles of Philosophy]]'' which begins {{lang|la|Veritatem inquirenti semel in vita da omnibus, quantum fieri potest, esse dubitandum.}} (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.{{efn|name="GutPrinc4391"}}) The phrase "ego cogito, ergo sum" appears in Part 1, article 7:[[File:1644_Principia_Philosophae.jpg|thumb|"ego cogito, ergo sum" with margin note in original (1644) Principia Philosophae]]{{Verse translation|{{lang|la|Sic autem rejicientes illa omnia, de quibus aliquo modo possumus dubitare, ac etiam, falsa esse fingentes, facilè quidem, supponimus nullum esse Deum, nullum coelum, nulla corpora; nosque etiam ipsos, non habere manus, nec pedes, nec denique ullum corpus, non autem ideò nos qui talia cogitamus nihil esse: repugnat enim ut putemus id quod cogitat eo ipso tempore quo cogitat non existere. Ac proinde haec cognitio, '''''ego cogito, ergo sum''''',{{efn|name="formatting"}} est omnium prima & certissima, quae cuilibet ordine philosophanti occurrat.|italic=unset}}{{efn|1=See original ''Principia'' manuscript [https://books.google.com/books?id=nHBTAAAAcAAJ&pg=PA3&q=%22ego%20cogito%22 here].}}|While we thus reject all of which we can entertain the smallest doubt, and even imagine that it is false, we easily indeed suppose that there is neither God, nor sky, nor bodies, and that we ourselves even have neither hands nor feet, nor, finally, a body; but we cannot in the same way suppose that we are not while we doubt of the truth of these things; for there is a repugnance in conceiving that what thinks does not exist at the very time when it thinks. Accordingly, the knowledge,{{efn|A 1647 French translation,<ref>{{cite book | author=Descartes | title=Principes de la philosophie | year=1647 | translator-first=Abbé Claude | translator-last=Picot | location=Paris| url = https://books.google.com/books?id=C7r-GKWF2xoC&q=abbe+Claude+Picot| isbn=9782711622313 }}</ref> published with Descartes's enthusiastic approval, substituted 'conclusion' for 'knowledge'.<ref>{{cite book | first1 =Valentine Roger | last1 = Miller | first2 = Reese P. | last2 = Miller | title = Descartes, René. Principles of Philosophy. Translated, with explanatory notes | year = 1983 | isbn = 978-90-277-1754-2 | pages = xi,5| publisher = Springer }}</ref>}} '''''I think, therefore I am''''',{{efn|name="formatting"}} is the first and most certain that occurs to one who philosophizes orderly.{{efn|name="GutPrinc4391"}}}}
Descartes's [[marginalia|margin note]] for the above paragraph is:

{{Verse translation|{{lang|la|Non posse à nobis dubitari, quin existamus dum dubitamus; atque hoc esse primum, quod ordine philosophando cognoscimus.|italic=unset}}|That we cannot doubt of our existence while we doubt, and that this is the first knowledge we acquire when we philosophize in order.{{efn|name="GutPrinc4391"}}}}

=== ''The Search for Truth by Natural Light'' ===
Descartes, in a lesser-known posthumously published work written ca. 1647,<ref>{{Citation | last = Gouhier | first = Henri | author-link = Henri Gouhier | title = ''La pensée religieuse de Descartes'' | year = 1924 | page = 319 | url = https://books.google.com/books?id=8Dw1AAAAIAAJ&pg=PA319}}</ref> originally in French with the title {{lang|fr|La Recherche de la Vérité par La Lumiere Naturale}} (''[[The Search for Truth by Natural Light]]'')<ref name="AT" /> and later in Latin with the title {{Lang|la|Inquisitio Veritatis per Lumen Naturale}},<ref>{{Cite book |last=Descartes |first=René |url=https://books.google.com/books?id=XDBnAAAAcAAJ&q=%22dubito%2C+ergo%22&pg=RA2-PP1 |title=Renati Des-Cartes Mvsicae compendivm |date=1683 |publisher=ex typogr. Blauiana |language=la}}</ref> provides his only known phrasing of '''the cogito''' as {{lang|la|'''cogito, ergo sum'''}} and admits that his insight is also expressible as '''''dubito, ergo sum''''':<ref name="Hintikka"/>
[[File:Dubito,_ergo_sum.jpg|thumb|"dubito, ergo sum, vel, quod idem est, cogito, ergo sum" in ''Inquisitio Veritatis per Lumen Naturale'']]
{{Verse translation|{{lang|la|... [S]entio, oportere, ut quid dubitatio, quid cogitatio, quid exsistentia sit antè sciamus, quàm de veritate hujus ratiocinii: '''''dubito, ergo sum''''', vel, quod idem est, '''''cogito, ergo sum'''''{{efn|name="formatting"}} : plane simus persuasi.|italic=unset}}|… [I feel that] it is necessary to know what doubt is, and what thought is, [what existence is], before we can be fully persuaded of this reasoning — '''''I doubt, therefore I am''''' — or what is the same — '''''I think, therefore I am'''''.{{efn|Translation by Hallam,<ref>{{Citation | last = Hallam | first = Henry | title = Introduction to the Literature of Europe in the 15th, 16th, and 17th Centuries | volume = II | edition = 2nd | page = 451 | year = 1843 | url = https://books.google.com/books?id=M4dZUnDvc1kC&q=%22%27%27%27%27%27I+doubt,+therefore+I+am%27%27%27%27%27,+or+what+is+the+same,+%27%27%27%27%27I+think,+therefore+I+am%27%27%27%27%27,+%22&pg=PA451}}</ref> with additions for completeness.}}}}

=== "{{Lang|la|ego cogito, ergo sum}}" or "{{Lang|la|cogito, ergo sum}}"? ===
Peter J. Markie notes: "Descartes stresses the first person in his premise twice in the Principles and once in his Reply to Mersenne. {{Lang|la|ego cogito, ergo sum}} . . . . (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.'"<ref>{{Cite journal |last=Markie |first=Peter J. |date=1982 |title=The Cogito Puzzle |url=https://www.jstor.org/stable/2107513 |journal=Philosophy and Phenomenological Research |volume=43 |issue=1 |pages=79–80 |doi=10.2307/2107513 |jstor=2107513 |issn=0031-8205|url-access=subscription }}</ref> 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 {{Lang|la|ego}} more than thirty times in the six Meditations."<ref>{{Cite book |last=Hatfield |first=Gary |url=https://books.google.com/books?id=pvEABAAAQBAJ&q=The+Routledge+Guidebook+to+Descartes%E2%80%99+Meditations |title=The Routledge Guidebook to Descartes' Meditations |date=2014-07-11 |publisher=Routledge |isbn=978-1-317-75485-5 |pages=69 |language=en}}</ref>

=== Other forms ===
The proposition is sometimes given as {{lang|la|dubito, ergo cogito, ergo sum}}. This form was penned by the French literary critic, [[Antoine Léonard Thomas]],{{efn|Thomas was known in his time for his great eloquence especially for éloges in praise of past luminaries.<ref>{{Cite book|last=Stephens|first=Henry Morse|url=https://books.google.com/books?id=SlkyAQAAMAAJ|title=Mirabeau. Vergniaud. Gensonné. Guadet. Louvet. Cambon|date=1892|publisher=Clarendon Press|pages=9|language=fr}}</ref>}} in an award-winning 1765 essay in praise of Descartes, where it appeared as "{{lang|fr|Puisque je doute, je pense; puisque je pense, j'existe}}" ('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''."{{efn|The 1765 work, ''Éloge de René Descartes'',<ref name=Thomas1765 /> by Antoine Léonard Thomas, was awarded the 1765 Le Prix De L'académie Française and republished in the 1826 compilation of Descartes's work, ''Oeuvres de Descartes''<ref name=Cousin1824 /> by [[Victor Cousin]]. The French text is available in [http://www.gutenberg.org/files/13846/13846-h/13846-h.htm more accessible format] at Project Gutenberg. The compilation by Cousin is credited with a revival of interest in Descartes.<ref name=Edinburgh1890 /><ref name=Descartes2007 />}} 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, {{lang|la|dubito, ergo cogito, ergo sum—res cogitans}} ("…—a thinking thing") extends the ''cogito'' with Descartes's statement in the subsequent ''Meditation'', {{lang|la|"Ego sum res cogitans, id est dubitans, affirmans, negans, pauca intelligens, multa ignorans, volens, nolens, imaginans etiam et sentiens…"}} ("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,]{{Efn|the French adds "loves, hates"; hence Veitch's inclusion despite its absence from the Latin here. see Cottingham, J. (ed), 1986, "Meditations on First Philosophy, with selections from Objections and Replies", p.24fn1.}} wills, refuses, who imagines likewise, and perceives").{{efn | This translation by [[John Veitch (poet)|Veitch]]<ref name="Veitch1880">{{cite book | author=Veitch, John | title=The Method, Meditations and Selections from the Principles of René Descartes | publisher=William Blackwood and Sons | year=1880 | location=Edinburgh | edition=7th | pages=115 | url = https://books.google.com/books?id=TjYCAAAAQAAJ&pg=PA115| author-link=John Veitch (poet) }}</ref> is the first English translation from Descartes as "I am a thinking thing".}} This has been referred to as "the expanded ''cogito''."<ref name=Kline1967 />{{efn|[[Martin Schoock]], in the 1642–43 controversy between Descartes and [[Gisbertus Voetius]], fiercely attacked Descartes and his philosophy in an essay.<ref>{{Citation | last = Schoockius | first = Martinus | title = Admiranda Methodus Novae Philosophiae Renati Des Cartes | year = 1643 | url = https://books.google.com/books?id=1PQGAAAAcAAJ}}</ref>
He wrote ''cogito, ergo sum, res cogitans'' and ''cogito, inquiro, dubito ergo sum'' as well as '''''cogito, ergo sum''''' (multiple times) in his 1652 ''De Scepticismo''.<ref>{{Citation | last = Schoockius | first = Martinus | title = De Scepticismo | page = 87 | year = 1652 | url = https://books.google.com/books?id=vW5WAAAAcAAJ&q=%22cogito+ergo+fum%22+cogito+-%22ego+cogito%22&pg=PA100}}</ref>}}

== Translation ==

=== "I am thinking" vs. "I think" ===
While the Latin ''cōgitō'' may be translated rather easily as "I think/ponder/visualize", {{nowrap|{{lang|fr|je pense}}}} does not indicate whether the verb form corresponds to the English [[simple present]] ("think") or [[Continuous and progressive aspects|progressive aspect]] ("is thinking").<ref>{{cite book |last=Pope |first=Rob |date=2013 |title=Textual Intervention: Critical and Creative Strategies for Literary Studies|url=https://books.google.com/books?id=HR7YAQAAQBAJ&q=%22I+think,+therefore+I+am%22+%22present+tense%22+descartes&pg=PA34 |publisher=Routledge |page=35 |isbn=978-1-135-08328-1}}</ref> Following [[John Lyons (linguist)|John Lyons]] (1982),<ref>{{cite book |last1= Lyons|first1= J.|year= 1982|chapter= Deixis and subjectivity: Loquor, ergo sum? |editor1-last= Jarvella|editor1-first= Rovert J. |editor2-last= Klein|editor2-first= Wolfgang |title= Speech, place, and action: Studies in deixis and related topics |pages= 101–224}}</ref> Vladimir Žegarac notes, "The temptation to use the simple present 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]]).<ref>{{cite thesis|last=Žegarac|first=Vladimir|date=1991|title=Tense, aspect and relevance|degree=PhD|url=http://discovery.ucl.ac.uk/1349786/1/363483.pdf |archive-url=https://web.archive.org/web/20151018113314/http://discovery.ucl.ac.uk/1349786/1/363483.pdf |archive-date=2015-10-18 |url-status=live|pages=84,85|institution=University of London}}</ref> 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."<ref>{{cite journal | last= Banfield|first= A. |date= 1998|title= The Name of the Subject: The "il"? | journal = Yale French Studies |issue= 93 | pages = 133–174 |doi= 10.2307/3040735 |jstor= 3040735 }}</ref> 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'."<ref name=Blackburn1999>{{cite book | author=Simon Blackburn | title=Think: A compelling introduction to philosophy | year = 1999 | url=https://archive.org/details/thinkcompellingi00bla_kzi | url-access=registration | quote="am thinking, therefore". | publisher=Oxford University Press| author-link=Simon Blackburn | isbn=978-0-19-976984-1 }}</ref>

The similar translation "I am thinking, therefore I exist" of Descartes's correspondence in French ("{{nowrap|{{lang|fr|je pense}}}}, {{nowrap|{{lang|fr|donc je suis}}}}") appears in ''The Philosophical Writings of Descartes'' by Cottingham et al. (1988).<ref name="CSMK III" />{{rp|247}}

The earliest known translation as "I am thinking, therefore I am" is from 1872 by [[Charles Porterfield Krauth]].<ref name=Krauth>{{cite journal|last=Krauth |first=Charles Porterfield |title=Notes in Class — Descartes |journal=The Penn Monthly |url=https://books.google.com/books?id=T75OAQAAMAAJ&pg=PA11|year=1872|publisher=University Press Company|volume=3|page=11}}</ref>{{efn|Krauth is not explicitly acknowledged as author of this article, but is so identified the following year by Garretson.<ref name="Garretson1873">{{cite book|author=James Edmund Garretson|title=Thinkers and Thinking|url=https://archive.org/details/thinkersandthin00garrgoog|quote=descartes he affirmed thinking.|year=1873|publisher=J.B. Lippincott & Company|page=[https://archive.org/details/thinkersandthin00garrgoog/page/n187 182]}}</ref>}}

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'."<ref>{{Cite web|last=Suzuki|first=Fumitaka|date=2012|title=The Cogito Proposition of Descartes and Characteristics of His Ego Theory|url=https://aue.repo.nii.ac.jp/?action=repository_action_common_download&item_id=106&item_no=1&attribute_id=15&file_no=1|url-status=dead|archive-url=https://web.archive.org/web/20180510050634/https://aue.repo.nii.ac.jp/?action=repository_action_common_download&item_id=106&item_no=1&attribute_id=15&file_no=1|archive-date=10 May 2018|access-date=6 May 2018|website=Aporia.byu.edu|publisher=Bulletin of Aichi Univ. of Education}}</ref>

=== "I exist" vs. "I am" ===
Alexis Deodato S. Itao notes that {{lang|la|cogito, ergo sum}} is "literally 'I think, therefore I am'."<ref>{{Cite journal|last=Itao|first=Alexis Deodato S.|date=2010|title=Paul Ricoeurs hermeneutics of symbols: A critical dialectic of suspicion and faith|url=http://www.kritike.org/journal/issue_8/itao_december2010.pdf |archive-url=https://web.archive.org/web/20120324060809/http://www.kritike.org/journal/issue_8/itao_december2010.pdf |archive-date=2012-03-24 |url-status=live|journal=Kritike|volume=4|issue=2|pages=1–17|doi=10.25138/4.2.a.1}}</ref> Others differ: 1) "[A] precise English translation will read as 'I am thinking, therefore I exist';<ref>{{cite thesis |type=PhD |last=del Pozo Baños |first= Marcos |date=2015 |title=My Mind, My Self, My Identity: A Task-Independent Neural Signature for Biometric Identification |publisher=Universidad De Las Palmas De Gran Canaria}}</ref> and 2) "[S]ince Descartes ... emphasized that existence is such an important 'notion,' a better translation is 'I am thinking, therefore I exist.'"<ref>{{cite thesis |type=PhD |last=Carpenter |first=John Michael |date=2012 |title=Remedying Some Defects in the History of Analyticity |publisher=Florida State University}}</ref>

=== 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]]''.<ref name="AT" /> It appeared there mid-sentence, uncapitalized, and with a comma. (Commas were not used in [[Classical Latin]]{{Efn|See ''Latin Punctuation in the Classical Age''.<ref>{{Cite web|title=Latin Punctuation in the Classical Age {{!}} Otha E. Wingo, E. Otha Wingo {{!}} download|url=https://u1lib.org/book/2832553/98631c|url-status=live|access-date=2021-12-25|website=u1lib.org|page=16|archive-url=https://web.archive.org/web/20211225053605/https://u1lib.org/book/2832553/98631c |archive-date=2021-12-25 }}</ref>}} but were a regular feature of scholastic Latin,<ref>{{Cite book|last=Saenger|first=Paul|url=https://books.google.com/books?id=w3vZaFoaa3EC&pg=PA1|title=Space Between Words: The Origins of Silent Reading|date=1997|publisher=Stanford University Press|isbn=978-0-8047-4016-6|pages=20|language=en}}</ref> the Latin Descartes "had learned in a Jesuit college at La Flèche.")<ref>{{cite book |last=Clarke |first=Desmond M. |url=https://books.google.com/books?id=_I-aBQAAQBAJ&q=%22the+only+Latin%22 |title=Narrative, Philosophy and Life |date=2015 |publisher=Springer |isbn=978-94-017-9348-3 |editor=Speight |editor-first=Allen |editor-link=Allen Speight |pages=177 |chapter=Descartes' Biography as a Guide to His ''Meditations''}}</ref> 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 [[Principles of Philosophy|''Principia Philosophiae'']], the proposition appears as '''''ego cogito, ergo sum'''''.<ref name="Descartes1644">{{cite book|author=Descartes, René|url=https://archive.org/details/ita-bnc-mag-00001403-001|title=Principia Philosophiae|publisher=apud Ludovicum Elzevirium|year=1644|pages=[https://archive.org/details/ita-bnc-mag-00001403-001/page/n68 30], 31|quote="Ego Cogito ergo sum".}}</ref>

== Interpretation ==
As put succinctly by [[Charles Porterfield Krauth|Krauth]] (1872), "That cannot doubt which does not think, and that cannot think which does not exist. I doubt, I think, I exist."<ref name=Krauth />

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 [[logical truth|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."<ref>{{Cite book |last=Lewes |first=George Henry |url=https://books.google.com/books?id=de8eP3HJIe8C&pg=PA142 |title=The History of Philosophy from Thales to Comte: Modern philosophy |date=1867 |publisher=Longmans, Green, and Company |language=en |quote=See [Descartes's] replies to the third and fifth series of Objections affixed to his Mediations.}}</ref>

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.

{{blockquote|But I have convinced myself that there is absolutely nothing in the world, no sky, no earth, no minds, no bodies.  Does it now follow that I, too, do not exist? No. If I convinced myself of something [or thought anything at all], then I certainly existed. But there is a deceiver of supreme power and cunning who deliberately and constantly deceives me.  In that case, I, too, undoubtedly exist, if he deceives me; and let him deceive me as much as he can, he will never bring it about that I am nothing, so long as I think that I am something.  So, after considering everything very thoroughly, I must finally conclude that the proposition, ''I am, I exist,'' is necessarily true whenever it is put forward by me or conceived in my mind. (AT VII 25; CSM II 16–17){{efn|name="abbreviations"|AT refers to Adams and Tannery;<ref name="AT" /> CSM II to Cottingham, Stoothoff, and Murdoch;<ref name="CSM II">{{Cite book|url=https://books.google.com/books?id=Q5P2lFaM8GgC&q=%22The+Philosophical+Writings+of+Descartes%22&pg=PP9|title=The Philosophical Writings of Descartes |volume=II |translator=Cottingham, J. |translator2=Stoothoff, R. |translator3=Kenny, A. |translator4=Murdoch, D. | date=1984 |publisher=Cambridge University Press|isbn=978-0-521-28808-8|language=en}}</ref> CSMK III to Cottingham, Stoothoff, Murdoch, and Kenny<ref name="CSMK III">{{cite book |title=The Philosophical Writings of Descartes |volume=III |translator=Cottingham, J. |translator2=Stoothoff, R. |translator3=Kenny, A. |translator4=Murdoch, D. |year=1991 |publisher=Cambridge University Press |isbn=978-0-521-42350-2 |url=https://books.google.com/books?id=Y3RRKISL810C&q=%22The+Philosophical+Writings+of+Descartes%22+Cottingham,+Stoothoff,+Murdoch,+and+Kenny}}</ref>}}
}}

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.<ref>''Self, Reason, and Freedom: A New Light on Descartes' Metaphysics'' Andrea Christofidou; chapter 2</ref>  As he puts it:

{{blockquote|[[Archimedes]] used to demand just one firm and immovable point in order to shift the entire earth; so I too can hope for great things if I manage to find just one thing, however slight, that is certain and unshakable. (AT VII 24; CSM II 16){{efn|name="abbreviations"}}}}

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 theory|substance]] with his [[ontology|ontological]] interpretation.

== Predecessors ==
Although the idea expressed in ''cogito, ergo sum'' is widely attributed to Descartes, he was not the first to mention it. In the late sixth or early fifth century BC, [[Parmenides]] is quoted as saying "For to be aware and to be are the same". (Fragment B3) [[Plato]] spoke about the "knowledge of knowledge" ([[Greek language|Greek]]: νόησις νοήσεως, ''nóesis noéseos'') and [[Aristotle]] explains the idea in full length:{{blockquote|But if life itself is good and pleasant…and if one who sees is conscious that he sees, one who hears that he hears, one who walks that he walks and similarly for all the other human activities there is a faculty that is conscious of their exercise, so that whenever we perceive, we are conscious that we perceive, and whenever we think, we are conscious that we think, and to be conscious that we are perceiving or thinking is to be conscious that we exist... (''[[Nicomachean Ethics]]'', 1170a 25 ff.)
}}
The Cartesian statement was interpreted to be an Aristotelian [[syllogism]] where the premise that all thinkers are also [[being]]s is not made explicit.<ref>{{cite web|url=https://literarydevices.com/syllogism/|title=Definition of Syllogism|date=3 October 2015|archive-url=https://archive.today/20210506053835/https://literarydevices.com/syllogism/|archive-date=6 May 2021|url-status=live|access-date=6 May 2021}}</ref>

In the early fifth century AD, [[Augustine of Hippo]] in ''[[City of God (book)|De Civitate Dei]]'' (book XI, 26) affirmed his certain knowledge of his own existence, and added: "So far as these truths are concerned, I do not at all fear the arguments of the Academics when they say, What if you are mistaken? For if I am mistaken, I exist."<ref>{{cite book |title=Augustine: The City of God Against the Pagans |page=484 |url=https://archive.org/details/cityofgodagainst0000augu_p2b5/page/484/mode/2up?view=theater |url-access=registration |translator=R. W. Dyson |publisher=Cambridge University Press |date=1998}}</ref>{{efn|Augustine makes a similar argument in the ''[[Enchiridion of Augustine|Enchiridion]]'', ch. 7, sec. 20.}} This formulation ({{lang|la|si fallor, sum}}) is sometimes called the Augustinian {{lang|la|cogito}}.<ref>{{Cite book|last=Matthews|first=Gareth|title=Thought's Ego in Augustine and Descartes|chapter-url=https://www.degruyter.com/document/doi/10.7591/9781501737152-005/html|chapter=3. The Augustinian Cogito|date=2019-05-15|pages=29–38|publisher=Cornell University Press|isbn=978-1-5017-3715-2|language=en|doi=10.7591/9781501737152-005|s2cid=242208218}}</ref> In 1640, Descartes wrote to thank Andreas Colvius (a friend of Descartes's mentor, [[Isaac Beeckman]]) for drawing his attention to Augustine:

{{blockquote|I am obliged to you for drawing my attention to the passage of St Augustine relevant to my ''I am thinking, therefore I exist''. I went today to the library of this town to read it, and I do indeed find that he does use it to prove the certainty of our existence. He goes on to show that there is a certain likeness of the Trinity in us, in that we exist, we know that we exist, and we love the existence and the knowledge we have. I, on the other hand, use the argument to show that this ''I'' which is thinking is an immaterial substance with no bodily element. These are two very different things. In itself it is such a simple and natural thing to infer that one exists from the fact that one is doubting that it could have occurred to any writer. But I am very glad to find myself in agreement with St Augustine, if only to hush the little minds who have tried to find fault with the principle.<ref name="CSMK III" />{{rp|159}}}}

Another predecessor was [[Avicenna]]'s "[[Floating man|Floating Man]]" [[thought experiment]] on human [[self-awareness]] and [[self-consciousness]].<ref name="Leaman">[[Hossein Nasr|Nasr, Seyyed Hossein]], and [[Oliver Leaman]]. 1996. ''History of Islamic Philosophy''. Routledge. p. 315. {{ISBN|0-415-13159-6}}.</ref>

The 8th century Hindu philosopher [[Adi Shankara]] wrote, in a similar fashion, that no one thinks 'I am not', arguing that one's existence cannot be doubted, as there must be someone there to doubt.<ref name="Radhakrishnan.S">[[Sarvepalli Radhakrishnan|Radhakrishnan, Sarvepalli]]. 1948. ''Indian Philosophy'' II. [[George Allen & Unwin Ltd]]. p. 476.</ref>

Spanish philosopher [[Gómez Pereira]] in his 1554 work ''[[Gómez Pereira#The immortality of the soul|Antoniana Margarita]]'', wrote "''nosco me aliquid noscere, & quidquid noscit, est, ergo ego sum''" ('I know that I know something, anyone who knows is, therefore I am').<ref>Pereira, Gómez. [1554] 1749. ''Antoniana Margarita'': "De Immortalitate Animae". p. 277.</ref><ref>López, Modesto Santos. 1986. "Gómez Pereira, médico y filósofo medinense." In ''Historia de Medina del Campo y su Tierra, volumen I: Nacimiento y expansión'', edited by E. L. Sanz.</ref>

== Critique ==
=== Use of "I" ===
In ''Descartes, The Project of Pure Enquiry'', English philosopher [[Bernard Williams]] provides a history and full evaluation of this issue.<ref name=":1" /> The first to raise the "I" problem was [[Pierre Gassendi]], who in his {{Lang|la|Disquisitio Metaphysica}},<ref>{{Cite book|last=Gassendi|first=Pierre|url=https://books.google.com/books?id=59cFzgEACAAJ|title=Disquisito metaphysica, seu dubitationes et instantiae adversus Renati Cartesii metaphysicam et responsa|date=1644|publisher=Vrin|language=la}}</ref> as noted by Saul Fisher, "points out that recognition that one has a set of thoughts does not imply that one is a particular thinker or another. …[T]he only claim that is indubitable here is the agent-independent claim that there is cognitive activity present."<ref>Fisher, Saul. [2005] 2013. "[https://plato.stanford.edu/entries/gassendi/ Pierre Gassendi]" (revised ed.). ''[[Stanford Encyclopedia of Philosophy]]''. Retrieved 17 June 2020.</ref>

The objection, as presented by [[Georg Christoph Lichtenberg|Georg Lichtenberg]], is that rather than supposing an entity that is thinking, Descartes should have said: "thinking is occurring." That is, whatever the force of the ''cogito'', Descartes draws too much from it; the existence of a thinking thing, the reference of the "I," is more than the ''cogito'' can justify. [[Friedrich Nietzsche]] criticized the phrase in that it presupposes that there is an "I", that there is such an activity as "thinking", and that "I" know what "thinking" is. He suggested a more appropriate phrase would be "it thinks" wherein the "it" could be an [[Dummy pronoun|impersonal subject]] as in the sentence "It is raining."<ref name="thinkingisoccurring">{{Cite web|url=http://aporia.byu.edu/pdfs/monte-Sum_ergo_cogito.pdf|title=Sum, Ergo Cogito: Nietzsche Re-orders Decartes|last=Monte|first=Jonas|date=2015|website=aporia.byu.edu|publisher=BYU|access-date=17 September 2016
|archive-url=https://web.archive.org/web/20220602112713/https://aporia.byu.edu/pdfs/monte-Sum_ergo_cogito.pdf
|archive-date=2 June 2022}}</ref>

=== Søren Kierkegaard ===
The Danish philosopher [[Søren Kierkegaard]] called the phrase a [[Tautology (logic)|tautology]] in his ''[[Concluding Unscientific Postscript]]''.<ref name=":0" />{{Rp|38–42}} He argues that the ''cogito'' already presupposes the existence of "I", and therefore concluding with existence is logically trivial. Kierkegaard's argument can be made clearer if one extracts the premise "I think" into the premises "'x' thinks" and "I am that 'x'", where "x" is used as a placeholder in order to disambiguate the "I" from the thinking thing.<ref>Schönbaumsfeld, Genia. ''A Confusion of the Spheres''. Oxford, 2007. p. 168-170.</ref>

Here, the ''cogito'' has already assumed the "I"'s existence as that which thinks. For Kierkegaard, Descartes is merely "developing the content of a concept", namely that the "I", which already exists, thinks.<ref name=":0">[[Søren Kierkegaard|Kierkegaard, Søren]]. [1844] 1985. ''[[Philosophical Fragments]]'', translated by P. Hong.</ref>{{Rp|40}} As Kierkegaard argues, the proper logical flow of argument is that existence is already assumed or presupposed in order for thinking to occur, not that existence is concluded from that thinking.<ref>Archie, Lee C. 2006. "Søren Kierkegaard, 'God's Existence Cannot Be Proved'." In ''Philosophy of Religion''. Lander Philosophy.</ref>

=== Bernard Williams ===
Williams himself claimed that what we are dealing with when we talk of thought, or when we say "I am thinking," is something conceivable from a [[Grammatical person|third-person]] perspective—namely objective "thought-events" in the former case, and an [[Objectivity (philosophy)|objective]] thinker in the latter. He argues, first, that it is impossible to make sense of "there is thinking" without relativizing it to ''something.'' However, this something cannot be Cartesian egos, because it is impossible to differentiate objectively between things just on the basis of the pure content of consciousness. The obvious problem is that, through [[introspection]], or our experience of [[consciousness]], we have no way of moving to conclude the existence of any third-personal fact, to conceive of which would require something above and beyond just the purely subjective contents of the mind.<ref name=":1">{{Cite book|last=Williams|first=Bernard Arthur Owen|url=https://books.google.com/books?id=eiTXAAAAMAAJ&q=%22there+is+thinking%22|title=Descartes: The Project of Pure Enquiry|date=1978|publisher=Penguin Books|isbn=978-0-14-013840-5|language=en}}</ref>

=== Martin Heidegger ===
As a critic of [[Cartesian Self|Cartesian subjectivity]], German philosopher [[Martin Heidegger]] sought to ground human subjectivity in death as that certainty which individualizes and authenticates our Being ([[Dasein]]). As he wrote in 1925 in ''History of the Concept of Time'':<ref>{{Cite book|last1=Heidegger|first1=Martin|url=https://www.jstor.org/stable/j.ctt16gzbw5|title=History of the Concept of Time: Prolegomena|last2=Kisiel|first2=Theodore|date=1985|publisher=Indiana University Press|isbn=978-0-253-32730-7|location=|pages=317|jstor=j.ctt16gzbw5}}</ref>{{blockquote|This certainty, that "I myself ''am'', in that I will die," is the basic certainty of [[Dasein]] itself. It is a genuine statement of Dasein, while ''cogito sum'' is only the semblance of such a statement. If such pointed formulations mean anything at all, then the appropriate statement pertaining to Dasein in its being would have to be ''sum moribundus'' [I am in dying], ''moribundus'' not as someone gravely ill or wounded, but insofar as I am, I am ''moribundus''. The ''MORIBUNDUS'' first gives the ''SUM'' its sense.}}

=== John Macmurray ===
The Scottish philosopher [[John Macmurray]] rejected the ''cogito'' outright in order to place action at the center of a philosophical system he entitled the Form of the Personal. "We must reject this, both as standpoint and as method. If this be philosophy, then philosophy is a bubble floating in an atmosphere of unreality."<ref>[[John Macmurray|Macmurray, John]]. 1991. ''The Self as Agent''. [[Humanity Books]]. p. 78.</ref> The reliance on thought creates an irreconcilable dualism between thought and action in which the [[:wikt:unity|unity]] of experience is lost, thus dissolving the integrity of our selves and destroying any connection with reality. In order to formulate a more adequate ''cogito'', Macmurray proposes the substitution of "I do" for "I think,"  ultimately leading to a belief in God as an agent to whom all persons stand in relation.

=== Alfred North Whitehead ===
In ''Process and Reality'', Whitehead wrote "Descartes in his own philosophy conceives the thinker as creating the occasional thought. The philosophy of organism inverts the order, and conceives the thought as a constituent operation in the creation of the occasional thinker. The thinker is the final end whereby there is the thought. In this inversion we have the final contrast between a philosophy of substance and a philosophy of organism."<ref>{{Cite book |last=Whitehead |first=Alfred North |url=https://books.google.com/books?id=uJDEx6rPu1QC&q=%22He+writes+%28Meditation+II%29%22 |title=Process and Reality |date=2010-05-11 |publisher=Simon and Schuster |isbn=978-1-4391-1836-8 |pages=150–151 |language=en}}</ref>

== In popular culture ==
<!--[[File:Billie Eilish - Therefore I Am.png|thumb|[[Billie Eilish]]'s 2020 single ''[[Therefore I Am (song)|Therefore I Am]]'': "You think that you're the man / I think, therefore I am"]]-->
In the [[short story]], ''[[I Have No Mouth, and I Must Scream]],'' by [[Harlan Ellison]], Gorrister, when asked what 'AM' means, says "At first it meant Allied Mastercomputer, and then it meant Adaptive Manipulator, and later on it developed [[sentience]] and linked itself up and they called it an Aggressive Menace, but by then it was too late, and finally called ''itself'' AM, emerging intelligence, and what it meant was I am ... ''cogito ergo sum'' ... I think, therefore I am."<ref>{{Cite web |title=AM by Harlan Ellison from I Have No Mouth And I Must Scream |url=http://www.technovelgy.com/ct/content.asp?Bnum=2380 |access-date=2024-03-11 |website=www.technovelgy.com}}</ref>

In the [[Anime|Japanese animated]] television series, [[Ergo Proxy]], a [[computer virus]] that affects the autoreivs, the series' version of [[robot]]s, known as the Cogito virus begins infecting the autoreivs, which is named such due to the fact that it makes the infected [[Consciousness|conscious]], and experience [[emotion]]s as a human would.

In [[Monty Python]]'s [[Bruces' Philosophers Song]], one of the lyrics jokingly quotes [[René Descartes|Descartes]]'s axiom as "I drink therefore I am."<ref>{{Citation |title=Monty Python – Bruces' Philosophers Song |url=https://genius.com/Monty-python-bruces-philosophers-song-lyrics |access-date=2024-03-11}}</ref>

In the episode "[[Work Experience (The Office)|Work Experience]]" of ''[[The Office (British TV series)|The Office]]'', [[David Brent]] says, "We are the most efficient branch, cogito ergo sum, we'll be fine."<ref>{{Cite web |title=The Office: Season 1, Episode 2 script {{!}} Subs like Script |url=https://subslikescript.com/series/The_Office-290978/season-1/episode-2-Work_Experience |access-date=2024-03-11 |website=subslikescript.com}}</ref>

In the video game [[Honkai: Star Rail]], Dr. Ratio (real name Veritas Ratio), a playable character and, according to in-game lore, a [[Philosophy|philosopher]],<ref>{{Cite web |title=Honkai: Star Rail official website {{!}} May this journey lead us starward |url=https://hsr.hoyoverse.com/en-us/character?worldIndex=2&charIndex=2 |access-date=2024-05-10 |website=hsr.hoyoverse.com |language=en-us}}</ref> has a skill, named "Cogito, Ergo Sum".<!--

The lyrics and title of singer-songwriter [[Billie Eilish]]'s 2020 single ''[[Therefore I Am (song)|Therefore I Am]]'' references Descartes' dictum.<ref>{{cite web|url=https://www.nme.com/reviews/track/billie-eilishs-new-song-therefore-i-am-is-review-2815185|title=Billie Eilish's new song 'Therefore I Am' is an existential banger (and might boast her best chorus yet)|last=Smith |first=Thomas|website=[[NME]]|date=November 12, 2020|access-date=March 29, 2024}}</ref><ref>{{cite web|url=https://www.seventeen.com/celebrity/music/a34658382/billie-eilish-calls-out-body-shamers-new-song-therefore-i-am-lyrics/|title=Billie Eilish Calls Out Her Body Shamers in the Lyrics to Her New Song 'Therefore I Am'|last=Twersky|first=Carolyn|website=[[Seventeen (American magazine)|Seventeen]]|date=November 12, 2020|access-date=March 29, 2024}}</ref>
-->

== See also ==
{{Portal|Philosophy}}
* {{anl|Academic skepticism}}
* {{anl|Apperception}}
* {{anl|Be, and it is}}
* {{anl|Brain in a vat}}
* {{anl|Cartesian doubt}}
* {{anl|Floating man}}
* {{anl|I Am that I Am}}
* [[Tat Tvam Asi]] – "You are that"
* {{anl|The Animal That Therefore I Am|''The Animal That Therefore I Am''}}
* {{anl|Vertiginous question}}
* {{anl|I have no mouth and I must scream}}

== Notes ==
{{Notelist | refs=

{{efn|name="GutPrinc4391" | Translation from {{Gutenberg | no= 4391 | name=The Principles of Philosophy | bullet=none}}.}}

{{efn |name="formatting" |''Cogito'' variant highlighted to facilitate comparison; the phrase was italicized in the original.}}
}}

== References ==
{{reflist|2|refs=
<ref name="Cress1986">{{cite book|author=Descartes, René | title=Discourse on Method and Meditations on First Philosophy|url=https://books.google.com/books?id=r7F27Ra9ecoC&pg=PA65|others=Translated by Donald A. Cress|year=1986|isbn=978-1-60384-551-9|pages=65
| publisher=Hackett}}</ref>

<ref name="Thomas1765">{{cite book|author=Thomas, Antoine Léonard |title=Éloge de René Descartes|publisher=E. van Harrevelt |pages=[https://archive.org/details/b30386305/page/24/mode/2up?q=j’exifte+ 23–24] |year=1765}}</ref>

<ref name="Cousin1824">{{cite book|author=Cousin, Victor | title=Oeuvres de Descartes|url=https://books.google.com/books?id=m4eiieOMwQIC&pg=PA60|year=1824}}</ref>

<ref name="Edinburgh1890">{{cite book|title=The Edinburgh Review for July, 1890 … October, 1890|
page=469|publisher=Leonard Scott Publication Co.|url=https://books.google.com/books?id=fKjPAAAAMAAJ&pg=PA469|year=1890}}</ref>

<ref name="Descartes2007">{{Cite book|last1=Bohemia|first1=Princess Elisabeth of|url=https://books.google.com/books?id=nUqHckXFyxUC&q=%22The+Correspondence+between+Princess+Elisabeth+of+Bohemia+and+Ren%C3%A9+Descartes%22|title=The Correspondence between Princess Elisabeth of Bohemia and René Descartes|last2=Descartes|first2=René|date=2007-11-01|publisher=University of Chicago Press|isbn=978-0-226-20444-4|language=en}}</ref>

<ref name="Kline1967">{{cite book|author=Kline, George L. |title=Naturalism and Historical Understanding |page=85 |chapter=Randall's Interpretation of the Philosophies of Descartes, Spinoza, and Leibniz |editor1=John Peter Anton|publisher=SUNY Press|year=1967}}</ref>

}}

== Further reading ==
* [[William Emmanuel Abraham|Abraham, W. E.]] 1974. "Disentangling the Cogito." ''[[Mind (journal)|Mind]]'' 83:329.
* Baird, Forrest E., and [[Walter Kaufmann (philosopher)|Walter Kaufmann]]. 2008. ''From Plato to Derrida''. Upper Saddle River, NJ: [[Pearson Prentice Hall]]. {{ISBN|978-0-13-158591-1}}.
* Boufoy-Bastick, Z. 2005. "Introducing 'Applicable Knowledge' as a Challenge to the Attainment of Absolute Knowledge." ''Sophia Journal of Philosophy'' 8:39–52.
* Christofidou, A. 2013. ''Self, Reason, and Freedom: A New Light on Descartes' Metaphysics''. Routledge.
* Hatfield, G. 2003. ''Routledge Philosophy Guidebook to Descartes and the Meditations''. Routledge. {{ISBN|0-415-11192-7}}.
* [[Søren Kierkegaard|Kierkegaard, Søren]]. [1844] 1985. ''[[Philosophical Fragments]]''. Princeton. {{ISBN|978-0-691-02036-5}}.
* — [1846] 1985. ''[[Concluding Unscientific Postscript to Philosophical Fragments|Concluding Unscientific Postscript]]''. Princeton. {{ISBN|978-0-691-02081-5}}.

== External links ==
{{wikiquote}}
* {{Cite SEP|url-id=descartes-epistemology|title=Descartes's Epistemology}}

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