It’s pretty clear that our subjective experiences stem from activities going on in the brain. You can even test this out by physically altering the brain in various ways, and its owner will report different subjective experiences. Consider, for instance, a concussion: damage to the brain can lead to memory loss, vision impairment, pain, and other complications.
The subjectivity that stems from the brain either emerges when all the brain’s circuitry is wired in harmony, or it emerges granularly. Most phenomena in the physical world are granular, so I suspect that subjective experience boils down to smaller subcomponents than the entire brain itself. Additionally, the multifaceted nature of subjective experiences themselves supports this. Further, there are a ridiculous number of combinations of emotions and qualia for an emergent model to account for—a granular theory of consciousness much more simply explains the nature of our subjective experiences.
If consciousness is indeed granular, then we should be left wondering where that granularity ends. To answer this, let’s consider a thought experiment: for most neurological systems we can choose, we can probably slightly alter it in a particular way and the subjectivity wouldn’t change. For instance, I highly doubt that there is not at least one carbon atom in a group of neurons that one couldn’t remove without altering any of the subjectivity that is produced. When we’ve finally found that simplest system which we cannot be altered in any way without destroying the subjectivity, we know we have found the simplest objects that support qualia. These structures have a theoretical minimal description length and can theoretically be described by the fundamental theory of everything we might eventually uncover.
Hence, when we talk about how we want to propagate welfare, we really mean that we want to propagate certain fundamental physics structures and their operations. These structures and their operations are not necessarily only those that perfectly form a typical human brain—slight modifications may lead to more desirable and more energetically efficient subjective experiences.
Beyond improving the welfare and instrumental utility of human beings, there is another way to do good: create structures that facilitate those fundamental physics operations which produce the most well-being. These idealized physical structures optimized for well-being have been termed hedonium or orgasmium. A simple way to do a lot of good may be to design and produce these structures/beings. They could be brains on chips where we reliably know that there is the subjective experience of intense bliss. These don’t have to replace people and producing these don’t have to be our only goal. Our moral uncertainty and utility function are too complicated to require just that. We can justifiably focus on improving human welfare and instrumental utility AND create orgasmium.