Descartes postulated that he is mental substance which is completely separate from physical substance. This is an idea that hearkens back to Ancient Gnosticism, and this notion of the disembodied Cartesian Subject, completely divorced from the physical world, is rejected by almost all philosophers, including me.

Descartes did say, “What am I? I am a thinking thing,” and that is probably why you think I am being Cartesian. But Descartes saw the thinking thing as entirely rational, perfect intellect incapable of error as long as it does not allow itself to be hindered by will. So, for Descartes, the Self is pure intellect in tension with the will, and the body is just kind of there.

I do not see the will as detached from the Self. When I use the term “thought” I am not using it as Descartes does but as denoting all of our mental activity, including emotions and will. I do not divorce the will from the Self. I also do not see the Self as disembodied, obviously it is embodied, but I do not reduce Self to the body, as materialists do.

As for Zen, it is a combination of Daoism and Buddhism, and its views are an interesting blend, and sometimes muddle, of two ontologies. The word game that you paraphrase is from the Zen tradition, but like word games of single hands clapping, it has only the surface appearance of doing something clever. You do not “ask thought” anything (though if you did, that would show there is a self in distinction from yourself with which you can have a dialogue, which is an interesting thought). When you reflect on what is real, no entity pops up and proclaims “I Am” like the God of Abraham. Thinking is process, and my view of it comes not from Descartes but from Bergson, Husserl, and Scheler. When you reflect on what is real, you are being real. “Si fallor, sum,” said Augustine, thinking clearly.