How do we ever understand anything? Almost always, I think, by using one or another kind of analogy — that is, by representing each new thing as though it resembles something we already know. Whenever a new thing's internal workings are too strange or complicated to deal with directly, we represent whatever parts of it we can in terms of more familiar signs. This way, we make each novelty seem similar to some more ordinary thing. It really is a great discovery, the use of signals, symbols, words, and names. They let our minds transform the strange into the commonplace.
Suppose an alien architect has invented a radically new way to go from one room to another. This invention serves the normal functions of a door, but it has a form and mechanism so far outside our experience that to see it, we would never recognize it as a door, nor guess how to use it. All its physical details are wrong. It is not what we normally expect a door to be — a hinged, swinging, wooden slab set into a wall. No matter: just superimpose on its exterior some decoration, symbol, icon, token, word, or sign that can remind us of its use. Clothe it in a rectangular shape, or add to it a push-plate lettered EXIT in red and white, and every visitor from the planet Earth will know, without a conscious thought, just what that pseudoportal's purpose is, and use it as though it were a door.
At first it may seem mere trickery, to assign the symbol for a door to an invention that is not really a door. But we're always in that same predicament. There are no doors inside our minds, only connections among our signs. To overstate the case a bit, what we call consciousness consists of little more than menu lists that flash, from time to time, on mental screen displays that other systems use. It is very much like the way the players of computer games use symbols to invoke the processes inside their complicated game machines without the slightest understanding of how they work.
And when you come to think about it, it scarcely could be otherwise! Consider what would happen if we actually could confront the trillion-wire networks in our brains. Scientists have peered at tiny fragments of those structures for many years, yet failed to comprehend what they do. Fortunately, for the purposes of everyday life, it is enough for our words or signals to evoke some useful happenings within the mind. Who cares how they work, so long as they work! Consider how you can scarcely see a hammer except as something to hit with, or see a ball except as something to throw and catch. Why do we see things, less as they are, and more in view of how they can be used? It is because our minds did not evolve to serve as instruments for science or philosophy, but to solve practical problems of nutrition, defense, procreation, and the like. We tend to think of knowledge as good in itself, but knowledge is useful only when we can exploit it to help us reach our goals.