Why do we speak as we do?
It is because, all along the line, we mean by the real tree, not what is given to the sense of sight, but something for which this stands as a sign.

This something must be given in our experience somewhere, we must be able to perceive it under some circumstances or other, or it would never occur to us to recognize the visual experiences as _signs_, and we should never say that in being conscious of them in succession we are looking at the same tree.

They are certainly not the same with each other; how can we know that they all stand for the same thing, unless we have had experience of a connection of the whole series with one thing?
This thing for which so many different visual experiences may serve as signs is the thing revealed in experiences of touch.

When we ask: In what direction is the tree?
How far away is the tree?
How big is the tree?
we are always referring to the tree revealed in touch.

It is nonsense to say that _what we see_ is far away, if by what we see we mean the visual experience itself.