Can a sighted person explain to me how you can see something is there, but also see through it? How are both of these things possible at the same time I do not understand!

I have a follow up question. If a window has a mesh screen, can you see through that? Or is everything broken up and difficult to make out.

Also what about dogs? My dog would stop at a glass door and sit and look through it. Could she see it was there? Or did she have enough contextual knowledge to know that it wasn't something she could walk through. Can dogs make these kinds of leaps in terms of reasoning?

This entire thread reminds me of the time we were on holiday and we were in a shop and my dad bumped into a mirror and then automatically said sorry but it was his reflection. Lol over ten years and I still haven't forgotten.