Assuming consciousness is an evolved, purely physical property, what would be the evolutionary point of it? Why aren't all living beings simply automata? What exactly makes it necessary for us to have an experience of the world? You could have all of a human's functionality without the inner world, consciousness or whatever you want to call it.
To me it seems that the intricate chemical workings of the brain are purely designed to trick us into moving around and surviving. Why should living beings need chemicals to be motivated to eat and breed? You could develop a robot just doing these things without the need to trick it or motivate it.
This is where materialists' explanation for consciousness collapses for me. It just doesn't add up.