You write: "You seem to be saying that inner states (subjective experiences) are dependent on brain states for their “existence”. Let’s call brain states A (as seen from the third person perspective) and inner states B (as seen from the first person perspective). It can be easily shown that changes in A bring about changes in B. Is the opposite true? Do changes in B bring about changes in A?"I don't think the two should be thought of as separate or as having effects on one another. Inner states ARE brain states, and vice versa. They are the same ongoing process. Accepting this is hard because we have so much knowledge (subjective experience) about the inner states of our own brain, and so little knowledge about the inner states of brains in general scientific terms. But brains feel; they can be in states of compassion or angst or anger or trust and so on. It seems absurd to us that a physical object could have deep thoughts and feelings only because of our ignorance about the hyper-astronomical complexity of the brain.
Changes in our inner states are changes in our brain states. Meditation, for instance, seems to involve a profound reorganization of the frontal lobes, which you experience in enormous detail if you engage in meditation. This is what is meant by neuroplasticity - even in adult life the brain re-organizes; that's how we learn and change. Even the memory of what happened a moment ago requires plasticity; the brain re-organizing its synaptic connections to incorporate the new memory.
I think the deep inner brain states you emphasize in your work (contemplation, meditation, compassion, silence, unity, gratitude, trust) are challenging because they involve much more profound re-organization of the brain in which they occur. How can such re-organization be facilitated? Under what conditions is a brain most capable of deep change? I think answering these questions has always required and will continue to require deep human understanding of our brains as persons with bodies and social environments and rich lived experiences.
Part 1, part 2