I think I might know where you are going with strong vs. weak emergence.
One interesting thing about human consciousness is that it looks different from the first person than from the third person. That is, from a third person perspective we can observe a human being's behavior, we can observe (with the limited tools we have) which parts of the brain are using the most blood or emitting the most electricity. From a first person perspective, we can observe the impressions our brain makes of sensory input - how my computer monitor looks, the color and texture of my cubicle walls, the feeling of fingers pressing keys, the sounds of my coworkers talking and the air conditioner running.
We cannot, with current technology and knowledge, look at a functioning human brain and say "that brain is receiving data from the eyes that allow it to see tan cubicle walls, a black computer, and a glowing computer monitor". We have a general idea what neurons are doing the seeing, but not how they are representing what they see internally so that the "observer" part of the brain gets those impressions.
It's conceivable that we could, hypothetically, using computing power that is beyond current technology, simulate a human consciousness's reactions using a computer. That is, program a computer to respond to stimuli exactly the same way my brain does, such that you could have a conversation with it and it would respond just like Godless Dave would. William Gibson's "Mona Lisa Overdrive" touches on this concept. But would this simulation think and feel - internally, from the first person - the same way I do? It's an interesting question.
But even if the answer is no, that doesn't mean materialism is wrong. It just means the simulation didn't recreate what goes on - physically - inside my neurons. I very much suspect that is where the observing, thinking, and feeling happens, where the part of my brain is that thinks of itself as "I".
We don't know for sure that everything, including consciousness, has a materialist explanation. But given that, in all of human history, every time we have found an explanation for some phenomenon, it has been a materialist explanation, materialists like me are confident that all natural phenomena have material explanations.
So, in the scientific model, every part of human consciousness has a material explanation.