Why is "cogito" needed as a step in "dubito, ergo cogito, ergo sum"?

Question

If I understand it correctly, Descartes' statement "dubito, ergo cogito, ergo sum" ("I doubt, therefore I think, therefore I am") could be expanded as "I doubt; doubting is a form of thought; therefore, I think. I think; only beings can think, therefore I am."

If my understanding is correct, why is "cogito" ("I think") necessary as a step? Couldn't it simply be "dubito, ergo sum" ("I doubt, therefore I am")? "I doubt; only beings can doubt; therefore I am" seems to me to be equally valid.

This is not a duplicate of "Does the famous Descartes quote "dubito, ergo cogito, ergo sum" suggests secure knowledge of ones existence?" because that question addresses the validity of the statement as a whole, whereas this one addresses the necessity of the middle "cogito"/"I think" step.

Answer 1

My Latin is a bit rusty but from what I remember the -o ending of a verb refers to the first person singular. One might recognize that from words like "audio" (=I hear) or "video" (=I see).

So it's not just the gerund chain of "doubting therefore thinking, therefore being." But the "I" is already present in that thought. So "it's an I that does the doubting, therefore it is an I that does the thinking and therefor this I, is" ("sum" is also first person singular; "to be" already was an irregular verb in Latin).

I also took the liberty to change the phrase in the question from "dubito, ergo cogito" (I doubt, therefore I think) to "dubito, ergo sum" (I doubt, therefore I am), because that's how you translated it anyway.

Also if I look at the Wikipedia article Descartes seems to agree with you.

He originally published it in French as je pense, donc je suis (I think, therefore I am)

In the posthumously published The Search for Truth by Natural Light, he expressed this insight as 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").

Antoine Léonard Thomas, in a 1765 essay in honor of Descartes presented it as dubito, ergo cogito, ergo sum ("I doubt, therefore I think, therefore I am")

https://en.wikipedia.org/wiki/Cogito%2C_ergo_sum

Answer 2

Descartes was being pithy, and pithy isn't always good. But the logic, as I see it, is something like the following:

• We begin in a state of presumptuous indifference, accepting that everything (including our own existence) is exactly as we perceive it. This is unsatisfying because it's a mere assumption, not a product of reason.
• We doubt our perceptions in order to strip away mere appearances and find something solid we can begin with.
• We notice that the act of doubting is an act of thinking; we cannot (in fact or principle) doubt without thinking.
• The act of thinking is (thus) is foundational — not a presumption we can apply doubt to — and this foundational element shows that we exist.

Basically Descartes is saying that we can doubt everything except that we are thinking, and since we are (necessarily) thinking, there must be something that exists as us to do that action. Doubt must be specified before we can recognize it as a positive act.

Answer 3

Not even dubito is necessary, sum is enough in your practical approach.

In general, from a practical perspective, "cogito" and "dubito" are contingent. From a teleological one, both are useful.

In practice, x is not necessary in this tautology:

a=2x
x=3 
 =>
a=6

But having it provides causal information, that is, a teleological foundation. Or in simple words, a reason.

A second approach: doubt is "a state of mind", not a process in time. So, strictly, doubt does not imply thinking, therefore introducing though is necessary, even for a practical approach.