The key mutation of the schizophrenic psyche can be described as a disturbance of the first person-ness of the I-sense, i.e., of the sense of the "I" as personal subject of experience and of action. Under these circumstances, representations of things are not definitively experienced as "my" representations—with the self-evidence of belonging to me. This uncertainty of selfhood, specific to schizophrenia, cannot be reduced to a disability of intellect, logic, judgment, or memory. In the course of developing his argument, the (...) author criticizes philosopher Michel Henry's critique of Heidegger's (1961) interpretation of Descartes's cogito ergo sum. (shrink)