The way I explain Descartes’ deduction of the soul is like this: for Descartes, anything can be doubted. Take any mental representation (the blossoming cactus in front of me, my partner across the desk, the sparrow in the tree outside, the thought of a triangle, etc.). Since it is simply a representation of the thing in question, then it is possible that there is a disconnect between the representation in my mind and the thing itself. Furthermore, it might be the case that there is not any real thing that corresponds to the image I have in consciousness. In other words, it may be possible that everything that occurs to me, everything that strikes me, everything I hold in consciousness is pure fantasy. In fact, the world as such might not “really exist,” and even more disturbing, I might not exist at all. I have an image of myself that I represent to my consciousness by collating all my memories, my felt being, etc. but that all might be pure fantasy as well. I can, in other words, doubt the existence of essentially everything. That’s possible.
What saves Descartes is that there is one thing that it is logically impossible to doubt: i.e. the (f)act of doubting. This has to be understood as a verb. Doubting entails doubting, and there’s no way around that; or, if the act of doubt were doubted, then that (f)act would still exist. Now, since the structure of language is such that any verb requires a subject, Descartes reasons that some-one must be the actor carrying out the (f)act of doubt. But this is Descartes’ little trick: he deduced the absolute existence of thought, but because he is not interested in evaluating the nature of language, he misses the fact that maybe actions don’t entail subjects. Or at least that they don’t entail the atomized, liberal ego that he ends up presenting us at the end of the section on doubt. It feels, as Nietzsche points out, like he just wanted to get us to the existence of the soul and that the operation of doubt was only mediate, and not to be taken seriously.
So, Descartes’ doubt is a paradox:
On one hand, we say that it is “methodological.” This implies that it is “merely theoretical,” i.e. that no one should take the possibility of the non-reality of the self and the world very seriously. It only operates as a means to the end of proving the existence of God and the soul, and should not be taken as anything more serious.
On the other hand, we have to take it completely seriously, or else the whole thought experiment loses its force. If I didn’t, for example, really think that the “world” or “the self” or “God” might possibly be non-existent, then why bother giving a shit about the conclusion to which Descartes comes?
What if, instead, we did take it seriously, rather than leaning back on the “methodological” character of his doubt like infirm thinkers leaning on crutches? What if we take his doubt through to its conclusion: The structure of doubt does entail the absolute and immanent possibility of thought. The (f)act of doubting is evidence of a sui generis mind (broadly construed). But that does not necessarily entail the existence of an ego.
Descartes takes us to the deepest mystery of consciousness, as if we were jumping down a bottomless hole (a void?), and then bungee-cords us back onto the surface of things with the introduction of the ‘cogito’ as ‘ego.’
This experiment could just as easily result in the following conclusion: I think, therefore thought is an inherent property of the kosmos. In other words, if Descartes did not sneak the transcendental ego in through the back door, then we could take up his argument as an introduction to some kind of panpsychism.