At last we're coming close to capturing the meanings of things like chairs and games. We found that structural descriptions are useful, but they always seem too specific. Most chairs have legs, and most games have scores — but there are always exceptions. We also found purposeful descriptions to be useful, but they never seemed specific enough. Thing you can sit upon is too general to specify a chair, since you can sit on almost anything. Diverting activity is too broad for game — since there are many other ways to turn our minds from serious things. In general, a single definition rarely works.
Purposeful definitions are usually too loose. They include many things we do not intend. Structural definitions are usually too tight. They reject many things we want to include.
But we can often capture an idea by squeezing in from several sides at once, to get exactly what we need by using two or more different kinds of descriptions at the same time.
Our best ideas are often those that bridge between two different worlds!
I don't insist that every definition combine just these particular ingredients of structure and purpose. But that specific mixture does have a peculiar virtue: it helps us bridge between the ends we seek and the means we have. That is, it helps us connect things we can recognize (or make, find, do, or think) to problems we want to solve. It would be of little use to know that X's exist without some way to find and use them.
When we discussed accumulation, we saw that the concepts of furniture and money have reasonably compact functional definitions but accumulate many structural descriptions. Conversely, the concepts of square or circle have compact structural definitions but accumulate endless collections of possible uses.
To learn to use a new or unfamiliar word, you start by taking it to be a sign that there exists, inside some other person's mind, a structure you could use. But no matter how carefully it is explained, you must still rebuild that thought yourself, from materials already in your own mind. It helps to be given a good definition, but still you must mold and shape each new idea to suit your own existing skills — hoping to make it work for you the way it seems to work for those from whom you learn.
What people call meanings do not usually correspond to particular and definite structures, but to connections among and across fragments of the great interlocking networks of connections and constraints among our agencies. Because these networks are constantly growing and changing, meanings are rarely sharp, and we cannot always expect to be able to define them in terms of compact sequences of words. Verbal explanations serve only as partial hints; we also have to learn from watching, working, playing — and thinking.