Sentence:  Moreover, everyone will now accept that "some" aspects of our mental lives aren't even "accessible" to introspection. So transparent-access theorists need to provide an account o the distingction between those mental events that are, in principle, transparently accessible and those that are not. In effect, they need to provide us with a criterion of <WSD>introspectability</WSD>. 
Meaning of the word marked with <WSD> tags:  The quality of being accessible to self-examination and awareness.