I don't think it's pedantic, semantics are absolutely necessary for talking about this kind of thing precisely. I use the word perception to describe certain mental phenomena that we take as usually occurring in response to stimuli: sights, smells, etc. I'm not certain I totally understand your definition, but it sounds like you use the term to describe a type of process where sensory organs and the brain interact with the rest of the physical world to create mental phenomena—the same phenomena that I would call a perception. So because there aren't actual objects interacting with the sensory organs, then direct neural stimulation of the brain isn't a perception under your definition.
I can see where you are coming from with the idea that you could trigger those neural changes through some other process. It's an interesting idea, and I wonder if it could be true in practice somehow. Regardless, I'd still argue that you are manipulating the brain in one way or another to create a firsthand experience of seeing the color red. If you can explain redness fully in terms of physical systems and processes, then somebody having that firsthand experience for the first time shouldn't be thinking "oh, so that's what it is like to actually see red."
If these are purely physical processes, then that knowledge should have come along with your complete knowledge of all of physics. You should also know what it is like to have experiences that your brain doesn't have the hardware for, like a bat's experience of echolocation. It seems like an unfairly high bar to clear; how could you understand an experience without having it firsthand? But if you are committed to believing that conscious experience is a physical thing, then I think you are also committed to believing that it can be fully described in physical terms. Physicalists do have arguments that try to explain how you could pass that bar in theory or dodge the commitment altogether, but personally I think those arguments are pretty weak.
> If you can explain redness fully in terms of physical systems and processes, then somebody having that firsthand experience for the first time shouldn't be thinking "oh, so that's what it is like to actually see red."
I mean, I think I totally agree here. It's just that I think a "full" explanation would be able to include a description of "what it is like". And that somebody having the firsthand experience would think "Yup, that matches what I read it would be like". The cynical side of me feels that people who deny this will ever be possible are being a little pessimistic or unambitious.
> You should also know what it is like to have experiences that your brain doesn't have the hardware for, like a bat's experience of echolocation.
I don't think that this necessarily follows. The hardware defines limits to what an individual can understand. I will never have a full understanding of the location and velocity of every atom in the universe - even if in principle a physical description of it could exist - because my brain's hardware is insufficient to represent the model. Likewise I cannot expect a human to know what it's like to have a bat's experiences. But there could in principle be a super AI that can understand both human and bat experiences.
I can see where you are coming from with the idea that you could trigger those neural changes through some other process. It's an interesting idea, and I wonder if it could be true in practice somehow. Regardless, I'd still argue that you are manipulating the brain in one way or another to create a firsthand experience of seeing the color red. If you can explain redness fully in terms of physical systems and processes, then somebody having that firsthand experience for the first time shouldn't be thinking "oh, so that's what it is like to actually see red."
If these are purely physical processes, then that knowledge should have come along with your complete knowledge of all of physics. You should also know what it is like to have experiences that your brain doesn't have the hardware for, like a bat's experience of echolocation. It seems like an unfairly high bar to clear; how could you understand an experience without having it firsthand? But if you are committed to believing that conscious experience is a physical thing, then I think you are also committed to believing that it can be fully described in physical terms. Physicalists do have arguments that try to explain how you could pass that bar in theory or dodge the commitment altogether, but personally I think those arguments are pretty weak.