How can one say or verify that perception or subjective conscious experience of an objective real-world entity is necessarily the same or different for different people?
Though everyone identifies a particular wavelength of light as red(word, not conscious experience itself). It is entirely possible that different individuals might have different conscious experience for the same entity. They can identify it with the same notation or word(red) as an interface for communication.
If we assume that different individuals necessarily have the same conscious experience for the same entity. Then what is it in our mind that constitutes to same experience for similar objective entities in many different individuals of evolutionary sprouts?
Perception is not possible with mind and no matter (or) with matter and no mind. Hence Perception is an emergent property from the interactions of mind and matter. Lot has been already said and discussed in physics about the matter. It is time for research in the midway of physics and biology.