In learning their Societies-of-More, children learn various skills for comparing different qualities and quantities, like number and extent. It is tempting to try to summarize all that by saying that the children are learning something; we could call it the concept of quantity. But why do we feel we have to think of what we learn as things or concepts? Why must we thingify everything?
What is a thing? No one doubts that a child's building-block is a thing. But is a child's love for its mother also a thing? We're imprisoned by our poverty of words because even though we have good ways to describe objects and actions, we lack methods for describing dispositions and processes. We can scarcely speak of what minds do except as though they were filled with things that one could see or touch; that's why we cling to terms like concepts and ideas. I don't mean to say that this is always bad, for thing-ifying is indeed a splendid mental instrument. But for our present purpose, it is disastrous to assume that our minds contain some single concept of quantity. At different times, a word like more can mean many different kinds of things. Think about each of these expressions.
More colorful. More loud. More swift. More valuable. More complicated.
We speak as though these were similar, yet each of them involves a different, hard-earned web of ways to think! The phrase more loud might seem at first to be merely a matter of magnitude. But consider how the sound of a distant gong seems louder than a whisper near the ear — no matter that its actual intensity is less. Your reaction to what you hear depends not only on its physical intensity, but also on what your agencies conclude about the character of its source. Thus you can usually tell whether a gong is loud but distant, rather than soft but close, by unconsciously making assumptions about the origin of that sound. And all those other kinds of more engage equally subtle sorts of expertise.
Instead of assuming that our children come to crystallize a single concept of quantity, we must try to discover how our children accumulate and classify their many methods for comparing things. How do agents like Tall, Thin, Short, and Wide get formed into subagencies? To an adult, it seems natural to associate both being taller and being wider with being larger. But what prevents the child from inventing senseless concepts such as being Green and Tall and having recently been touched? No child has the time to generate and test all possible combinations to find which ones are sensible. Life is too short to do that many bad experiments! The secret is: always try to combine related agents first. Tall, Thin, Short, and Wide are all closely related, because they are all concerned with making comparisons between spatial qualities. In fact, they probably involve agencies that are close to one another in the brain and share so many agents in common that they'll naturally seem similar.