I disagree, Descartes believes that he had proven the existence of "a priori" thought, a place from which thinking could be conducted without doubt - that was the point of his project. That place is also the only reliable locus of personhood in his view. Future thinkers who talked about "embodied" thinking, were conceiving of a personhood that could exist before that a priori consciousness, rather than as a doubtful thing perceived by it.