His vision isn't ours.

When a boy of eight sees a horse, he doesn't see the correct biological object we intend him to see.

He sees a big living presence of no particular shape with hair dangling from its neck and four legs.

If he puts two eyes in the profile, he is quite right.

Because he does _not_ see with optical, photographic vision.
The image on his retina is _not_ the image of his consciousness.