You cannot be a rational subject without veto-control on the level of mental action.

The notion of a conscious model of oneself as an individual entity actively trying to establish epistemic relations to the world and to oneself, I think, comes very close to what we traditionally mean by notions like "subjectivity".

Subjectivity means to catch yourself in the act.

When you are simply observing your breath, you are perceiving an automatically unfolding process in your body. By contrast, when you are observing your wandering mind, you are also experiencing the spontaneous activity of a process in your body.

Of course, I strongly sympathized with Habermas and the philosophers representing the Frankfurt school, but I also saw the lack of conceptual clarity, and perceived the not-so-revolutionary self-importance in the epigones of Horkheimer, Adorno, and Habermas.

As far as inner action is concerned, we are only rarely truly self-determined persons, for the major part of our conscious mental activity rather is an automatic, unintentional form of behavior on the subpersonal level.

Conscious experience as such is an exclusively internal affair: Once all functional properties of your brain are fixed, the character of subjective experience is determined as well.