Descartes' phrase, "I think, therefore I am" is surely a translation,
but the phrase is usually quoted as "Cogito, ergo sum." This is Latin.
Didn't Descartes write in French? Please provide the words that
Descartes actually wrote, or confirm that this famous phrase in
English or Latin is merely a shorthand (for a longer explanation by
Descartes) that someone else provided later.

Hello gojohns

Descartes said "Je pense, donc je suis" - which translates exactly
into the familiar Latin and English phrases - in his "Discourse on
Method".  The same principle is laid out more fully in his later
Meditations, which he wrote in Latin, but without using the exact
phrase "cogito, ergo sum".


"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 pouvais la recevoir sans scrupule pour le
premier principe de la philosophie que je cherchois."
http://abu.cnam.fr/cgi-bin/donner_html?methode3

"But immediately afterwards I noticed that, while I wished in this way
to think everything was false, it was necessary that I—who was doing
the thinking—had to be something. Noticing that this truth—I think,
therefore I am—was so firm and so sure that all the most extravagant
assumptions of the sceptics would not be able to weaken it, I judged
that I could accept it without scruple for the first principle of the
philosophy I was looking for."
http://www.mala.bc.ca/~johnstoi/descartes/descartes1.htm


* * * *


"Descartes finally presented (in French) his rationalist vision of the
progress of human knowledge in the Discours de la méthode pour bien
conduire sa Raison et chercher la Vérité dans les Sciences  
(Discourse on Method) (1637). "

"A few years later, Descartes offered (in Latin) a more formal
exposition of his central tenets in Meditationes de Prima Philosophia
(Meditations on First Philosophy) (1641)"
http://www.philosophypages.com/ph/desc.htm

Meditation 2, paragraph 6:

"I am--I exist: this is certain; but how often? As often as I think"
http://philos.wright.edu/DesCartes/Meditation2.html#e6

"Ego sum, ego existo; certum est. Quandiu autem? Nempe quandiu cogito"
http://philos.wright.edu/DesCartes/Meditation2L.html#l6

Descartes' Meditations: trilingual edition
http://philos.wright.edu/DesCartes/Meditations.html

Meditation3, paragraph 36:

"sum res cogitans"
http://philos.wright.edu/DesCartes/Meditation3L.html

"I am a thinking being"
http://philos.wright.edu/DesCartes/Meditation3.html#e36


* * * *


"Cogito ergo sum is the famous phrase ascribed to the French
philosopher Rene Descartes. However, the phrase doesn't appear in his
writings at all. In his Meditations on First Philosophy Descartes,
writing in Latin, makes the claim "sum res cogitans" (I am a thinking
being). And in his Discourse on Method, he states in French "Je pense
donc je suis", which means "I am thinking therefore I am". However the
famous phrase itself was never issued from Descartes' pen.
Nevertheless, philosophers have taken to calling the claim "I think
therefore I am" the cogito."
http://www.everything2.com/index.pl?node=Cogito%20Ergo%20Sum


I hope this answers your question, but please let me know if you need
any clarification or if any links fail to work.

Regards - Leli


searches:

cogito ergo sum discourse meditations
://www.google.co.uk/search?q=cogito+ergo+sum+discourse+meditations&ie=UTF-8&oe=UTF-8&hl=en&btnG=Google+Search&meta=

then searches for the original texts