On the other hand, although if a sensory nerve be divided anywhere short of the brain, we lose the corresponding class of sense impression, we yet speak of many sense-impressions, such as form and texture, as existing outside ourselves.

How close then can we actually get to this supposed world outside ourselves?
Just as near but no nearer than the brain terminals of the sensory nerves.

We are like the clerk in the central telephone exchange who cannot get nearer to his customers than his end of the telephone wires.

We are indeed worse off than the clerk, for to carry out the analogy properly we must suppose him _never to have been outside the telephone exchange, never to have seen a customer or any one like a customer--in short, never, except through the telephone wire, to have come in contact with the outside universe_.

Of that 'real' universe outside himself he would be able to form no direct impression; the real universe for him would be the aggregate of his constructs from the messages which were caused by the telephone wires in his office.