I'd probably go along with Wiggs, above, in that there can be no such thing as an objective perception of reality; Nietzche 'there are no facts' comes to mind; but that is probably deeper than needed to counter Alan's core position, that 'that is how it seems', is enough to demolish all other reasoned arguments. 'How it seems' is evolutionary legacy, we perceive the world through a particular lens, unique to our species and unique to us each as individuals and that lens has no remit to be an accurate guide to external reality, in so far as such a thing could exist, rather it's remit is to allow us to navigate the world at minimum calorific cost. Our sense of vision for instance, only processes a tiny amount of incoming data and our internal imagery is constructed mostly from memory and expectation. So I don't put much weight by 'that is how it seems'.
I don't know if it would be a similar experience, when I put my hearing aids on each morning, for a moment when I switch them on the sound is tinny, this sound coming from the aids will not be changing, the miniture speakers can only reach their set level or capacity, but then brain takes over and turns this tinny sound reproduction into an approximation of it's preconcieved ideas, from, when I assume, from past memory of the sounds it remembers from when my hearing was having it's best days.
The sound correction my brain does is all performed without any concious effort on my part and manages to bring back normality, as near as is possible, to my hearing.
I believe the brain does something very similar when it patches over the blind hole in our vision where the rods and cones go through a hole in the retina to send their input via the optic nerve to the receptors within the brain.
I'm quite sure the brain does these things quite happily on it's own, can't see any logical reason to add anything magical.
ippy