That is, again, circular, and it is exactly the syllogism you said it’s not. You are still starting with the premise of “the very act of doubting whether or not ‘I’ exist”. Of course, we both agree that people exist, but that’s not the point, the point of the statement is to show that this belief is specifically a priori, meaning it can be derived without referencing any experiential data, but the syllogism itself is circular and shows nothing, and your reconstruction of it is circular in literally the identical way, as you are beginning with the assumption you are supposed to prove. You stated twice, quite clearly, that your premise in both cases is that the one doing the doubting/denial is “I,” and so you’ve already assumed “I” from the get-go, and so it is circular.

I could easily say, you are not a human but a magical alien. Don’t believe me? Well, the one doing the doubting is a magical alien, so you’ve implicitly conceded my point! It’s blatantly circular. “Doubting,” in terms of pure formal, does not automatically imply an “I” that is doing the doubting. You can justify it physically, by pointing out that doubting is a thing that requires an intelligent mind capable of judging things, but this is a physical argument, which is justified based upon knowledge of how these concepts relate in relation to what we have observed in the real world. The connection between “doubting” and “I” cannot be established a priori, only a posteriori.

Never bought into that statement because it’s obviously circular: “I” exists in both the conclusion and the premise, “I therefore I,” so it’s silly as a supposed proof that the self is a priori.

Genuine question: why should I even believe consciousness exists? This whole endeavor seems pointless without that justification.