Now, as I have put it before, the process of imagining seems fairly efficient. However, the efficiency presumes an unlikely mastery of abstraction. What does a dog know about “leash”? That flexible object with patterned blobs of (reflected) light that is necessary for leaving the boundaries of movement defined by the hard, cold, transparent force field (“fence”) , and connects another force field around Fido’s neck (“collar”) to master? And on and on.

Obviously, imagining is facilitated by understanding. The more powerful our abstractions, that more powerful and efficient are our imaginings.

Understanding can be of two types. It can be a categorization (“leash”), or a relationship (“necessary to leaving”). Relationships can be causal (establishing preconditions that determine an event), or probabilistic (defining the likelihood that an event will happen, when we cannot determine or control all conditions). The value of relationships is that they enable us to

• predict the range of outcomes that can be expected to occur, and
• focus our resources to control the risk of adverse outcomes.

Let’s again consider Fido’s leash as an example of the realization of a category. Whence arises this apprehension? This occurs in two kinds of realizations: “is-a” and “not is-a”. Fido interacts with master, and notices the magical restraint on his movement (“is-a”). He studies his environment. Many things in his environment, such as his dinner bowl, never seem to be associated with the magical restraint. These are to be disqualified (“not is-a”). Among those things that appear to be associated with the restraint, some are those that are always part of master (“not is-a”). On an important occasion, Fido breaks the magical restraint by lunging suddenly, and notices that something slaps his back and legs as he runs. He investigates, chewing, sniffing and scratching at the offending thing. Master arrives, and intervenes to end the investigations, taking the offending thing into his hand. And the magical restraint resumes (‘is “is-a”‘)!

Through experience and manipulation, Fido apprehends “leash”.

What is the apprehension of a “relationship”? The leash is related to Fido’s desire to explore territory. It is an enabling element.

Now, in a world in which Fido lives solely to go on walks, leash becomes the most important thing. If Fido can find it reliably on a certain table or inside a certain closet, he may ignore large portions of his domestic reality.

People in the thrall of romantic infatuation also experience this magical effect. No other prospective mate has meaning. The attentions of those candidates may be completely ignored. To those rejected suitors, it may seem as though they don’t exist at all to the subject of their intentions.

Where writ here in the small, so has been the course of human understanding. Primitive men lived in an extremely rich perceptual environment. In order to understand that environment, they had to narrow their perception of events. Objects successfully categorized became the focus of their perception, excluding the apprehension of phenomena that appeared less relevant to accomplishment of their goals.

In other words, living creatures, whether through Darwinian or Lamarckian processes, control their perceptions in order to improve their control of outcomes. With regards to human intellectual achievement, understanding has a cost in experience: our perceptions deepen, but narrow.

I have already observed that thought has allowed us to dramatically change the nature of the reality we inhabit. Possibilities and outcomes are far different now than they were when mankind first began the experiment of understanding. It may be impossible for us to apprehend exactly how different their perception of reality was from ours. I have found it instructive, however, to consider “Why?“