How do you know that the realities the majority of people perceive are highly highly similar? Language alone cannot be used to deduce this since perceiving and

How do you know that the realities the majority of people perceive are highly highly similar? Language alone cannot be used to deduce this since perceiving and constructing realities is rooted in the domain of qualia and the psyche. How do you now there are people for that matter other than brain(s) in vats ? The fact that you are willing to assume so much does not invalidate parent’s argument, merely exposes the flaws in yours.