"We cannot make a conclusive statement about reality unless we assume that our senses give us a PERFECT picture of reality."
Hmm.. so your senses are fooling you if you -think- you are falling when you step out of a twelfth floor window?
I'd say that is pretty real, and proves two things, gravity exists and is real, and that your sense are pretty accurate about it.
This really isn't difficult to follow.
How do you KNOW your senses are working perfectly? How do you KNOW it is giving you a perfect reflection of reality? The answer is: you don't.
You can't take "true reality" and "what we PERCEIVE as reality," put them next to each other, and compare them to see if they are the same. The point is, you can't CONFIRM that "perception of reality" = "true reality."