You don't seem to be responding to my point that's it's only a wall by consensus, not an objective thing that can be proven to exist in it's own right.
What I said both times is that the consensus over the wall is universal, in practice if not in theory, and a universal consensus that there is a wall is indistinguishable from an objectively real wall. The difference is semantic rather than empirically meaningful. I don't see what is gained by fussing over a consensus that nobody, not even people who deny objective reality, dissents from. Again, despite what we might theorize about it, find me someone who honestly acts as if the wall were not really there--I don't mean someone who merely says it's not objectively real, but who acts
like it is--and I will take seriously the notion that reality is not objective.
Let's try another thought experiment. Suppose you ask me how to get to Bakersville, and I say, "Take that road over there. However, when you turn around the bend, it's very important that you close your eyes for three seconds." Suppose you do exactly as I say, and when you reach the bend you close your eyes, thus preventing you from seeing the part I left out of my instructions: there is brick wall obstructing the road.
Since I didn't tell you about the wall, you are not aware of it; and since you don't see it as you're driving toward it, it is not something you are directly experiencing at that moment. From your perspective, it doesn't exist at all. As far as you're concerned, there is nothing to form a consensus over. What do you think will happen as your car continues toward it, and why will it happen?
Ask a physicist just how sold the wall is, and he'll tell you it's mostly empty space.
And yet the knowledge that the wall is mostly empty space does not prevent the physicist from referring to an "it" in the first place, nor from taking its measurements, nor from averting his trajectory if he sees his car is heading toward it, etc.
If you existed in a time scale of millions of years, the wall would have burst in and out of existence without your notice.
So you admit there is an existence for it to burst in and out of?