How does an insubstantial word like apple lead you to think of a real thing — an object of a certain size that is red, round, sweet, and has a shiny, thin-peeled skin? How could a plain acoustic sound produce such complex states of mind, involving all those qualities of color, substance, taste, and shape? Presumably, each different quality involves a different agency. But then — in view of all we've said about why different agents can't communicate — how could such varying recipients all understand the selfsame messages? Do language- agents have unusual abilities to communicate with different kinds of agencies?
Many people have tried to explain language as though it were separate from the rest of psychology. Indeed, the study of language itself was often divided into smaller subjects, called by traditional names like syntax, grammar, and semantics. But because there was no larger, coherent theory of thinking to which to attach those fragments, they tended to lose contact with one another and with reality. Once we assume that language and thought are different things, we're lost in trying to piece together what was never separate in the first place. This is why, in the following pages, I'll put aside most of the old language theories and return to the questions that led to them:
How are words involved with mental processes? How does language enable people to communicate?
In the next few sections, we'll introduce two kinds of agents that contribute to the power of words. The first kind, called polynemes, are involved with our long-term memories. A polyneme is a type of K-line; it sends the same, simple signal to many different agencies: each of those agencies must learn, for itself, what to do when it receives that signal. When you hear the word apple, a certain polyneme is aroused, and the signal from this polyneme will put your Color agency into a state that represents redness. The same signal will set your Shape agency into a state that represents roundness, and so forth. Thus, the polyneme for apple is really very simple; it knows nothing whatever about apples, colors, shapes, or anything else. It is merely a switch that turns on processes in other agencies, each of which has learned to respond in its own way.
Later we'll discuss another type of language-agent that we'll call an isonome. Each isonome controls a short-term memory in each of many agencies. For example, suppose we had just been talking about a certain apple, and then I said, Please put it in this pail. In this case, you would assume that the word it refers to the apple. However, if we had been discussing your left shoe, you would assume it referred to that shoe. A word like it excites an isonome whose signal has no particular significance by itself, but controls what various agencies do with certain recent memories.