You write: "Do you mean that “feelings of meaninglessness” and “feelings of compassion” are nothing other than electrochemical activity? Can we fully understand “feelings of meaninglessness” and “feelings of compassion” by just grasping what is going on in the brain, “a network of neurons”?".. Human history reveals that techniques for changing inner (subjective) states [contemplation, meditaion, compassion] have played a major role in the evolution of culture. Are these techniques now something of the past? What is the next step in the evolution of culture? Where are we going?"The key, I think, is in the phrase "nothing other than". It implies a destructive reductionism. But brain states are hyper-astronomical in their complexity and profoundly sublime and beautiful in their dynamics. Neuroscience does not reduce rich inner states to simple things - it shows that rich inner states are astonishingly complex processes in the brain. That's what I meant when I said "inner states are brain states, no more no less". The phrase "by just grasping what's going on in the brain" similarly suggests that such understanding is readily available. It's not: we are nowhere near a good understanding of the brain. We don't even, as you point out, understand how snails learn to chew, much less the feelings they experience as they learn.
An understanding of feelings of meaninglessness or compassion would be utterly incomplete without understanding brains as persons with deep relationships to other persons, to their history, to culture and language, and to his or her subjective experience. We know very little about how to relate brains to other brains, to their upbringing, or to their inner life. We do nevertheless know that inner states are brain states; that they can be transformed or turned off by altering the state of the brain. As far as I'm concerned this doesn't degrade subjective experience, or reduce its significance or complexity, quite the opposite. However, I do very much think that our cultural transition from souls to brains will be a profound challenge, a real adventure. Neuroscience only really got going in the 1990s, and we will learn much much more in the years ahead. Inner states will no longer be completely subjective or private.
The challenge in all this is to avoid a nihilism that exists at the core. Descartes failed to do so when he concluded that animals, lacking souls, were "just machines" that could not have feelings, and proceeded to carry out vivisections and experiments of the most hellish kind on dogs and other species. This nihilism says that if all our rich inner states are "nothing but" brain states, then they are meaningless, worthless, and can be abused. This nihilist temptation is amplified by the shortcuts of consumerism and new technology, and by the sheer complexity of the neuroscientific world-view that is emerging. Therefore, as we travel through this cultural transition, it will be more important than ever to emphasise the reality and importance of deep inner states, and the role of contemplation, meditation, compassion, silence, unity, gratitude and trust.
Part 1, part 3