(For the purpose of this thread, I am taking as a given that dualism is false, that there is nothing incorporeal attached to people to make consciousness possible. If you reject that premise, please make that argument elsewhere.)
Moral agency is attributed to all normally functioning human adults. Such moral agents can understand right and wrong, and make decisions for which they can be held morally culpable. Unlikely a rock falling of a cliff that kills someone, a person who throws a rock off a cliff and kills someone can rightly be blamed.
But the moral agency of that person is just a result of the network of cells in her nervous system: a special set of connections between special kinds of cells produce a machine that can receive information, process it, and act on it. Stimuli excite receptors, which propagate signals across the network. Each new signal strengthens or weakens connections, refining the network to react differently to subsequent stimuli. These refinements over time become concepts, words, ideas, understanding, and from that understanding we impute moral agency and moral responsibility.
But such networks are not limited to the brains of moral agents. Inter-brain connections, be they biological, economic, social, technological, similarly create networks, that receive stimuli, and learn and respond in ways that approximate understanding.
Why, then, limit moral agency, and moral worth, to only those brain-like networks that actually happen to be brains? It seems clear that a brain recreated in silica would have all the moral agency of the original carbon-based brain. Shouldn’t a non-brain network that nonetheless possesses many of the properties of a brain, that seems to ‘make choices’ in the same way that a brain does, also be granted such agency? Shouldn’t all such networks be granted moral agency? Isn’t it some other property, some property of network topology, that makes brains worthy of moral agency?