I would like to highlight the observation that

I would like to highlight the observation that there may be no way to know if Alice's green is the same qua qualia as Bob's green. If qualia ontologically exist then there may be no (ontological) fact of the matter as to whether they are the same. In this case the assumption of an objective perspective from which truths may be derived about the world must be dropped, and contextual ontologies become appropriate. There is a formal theory of contextual logic (different domains of the for-all quantifier are labeled by selected subjects of the theory), that hasn't been exploited yet.