The essay examines the impact of thought insertion on typical conceptions of self-consciousness. Stephens and Graham have recently argued that thought insertion is compatible with the inseparability thesis, which maintains that with regard to self-consciousness subjectivity is a proper part of introspection--introspection and subjectivity are inseparable. They argue that thought insertion is an error of agency and not an error of subjectivity. The essay contends that even if they are correct in their interpretation that thought insertion is an error of (...) agency rather than subjectivity, which is unlikely, they are incorrect to maintain that it is not also an error of subjectivity. Evidence is put forth to indicate that thought insertion is, at best, a mistake of agency and subjectivity. It is concluded that thought insertion is incompatible with the inseparability thesis, and a new inseparability thesis is thereby postulated. (shrink)