So that's interesting. Behaviorism, for instance, was actually an oppressive "science" of the 20th century because it was ideologically opposed to even acknowledging the existence of subjective mental states. The proponents of Behaviorism felt that subjective mental states were inherently unscientific and they wanted to turn Psychology into a respectable science.

Behaviorists were operating under the misconception that something can't be both subjective and objective at the same time. It took Cognitive Psychology to rescue us from this sorry state of affairs. But for years, those who wanted to do Cognitive Psychology academically were blocked from publishing and getting tenure, etc., by the entrenched Behaviorist establishment.

These days we know that via using FMRI, for instance, psychologists and neuroscientists can often determine objectively more about some of your own thoughts than you yourself might know. Or they can sometimes know what you will come to decide before you believe yourself to have decided. Etc.

But certain mental states (i.e., phenomenal ones) seem to have an inherently subjective component that cannot be studied objectively at all. Or at least that's what someone who believes in the "hard problem of consciousness" will say. Others will say, "Pshaw!"