Nerves and Postmen
A letter, so long as it is connected with one set of nerves, is one thing; loose it from connection with those nerves—open your fingers and drop it in the opening of a pillar box—and it becomes part and parcel of another nervous system. Letters in transitu contain all manner of varied stimuli and shocks, yet to the postman, who is the nerve that conveys them, they are all alike, except as regards mere size and weight. I should think, therefore, that our nerves and ganglia really see no difference in the stimuli that they convey.
And yet the postman does see some difference: he knows a business letter from a valentine at a glance and practice teaches him to know much else which escapes ourselves. Who, then, shall say what the nerves and ganglia know and what they do not know? True, to us, as we think of a piece of brain inside our own heads, it seems as absurd to consider that it knows anything at all as it seems to consider that a hen’s egg knows anything; but then if the brain could see us, perhaps the brain might say it was absurd to suppose that that thing could know this or that. Besides what is the self of which we say that we are self-conscious? No one can say what it is that we are conscious of. This is one of the things which lie altogether outside the sphere of words.
The postman can open a letter if he likes and know all about the message he is conveying, but, if he does this, he is diseased qua postman. So, maybe, a nerve might open a stimulus or a shock on the way sometimes, but it would not be a good nerve.