Section 8.1. Hacks 75-80

8.1. Hacks 75-80

What makes "this" a word, rather than being simply the adjacently written letters t, h, i, s? Or, to ask a similar question, why should we see a single dog running across a field rather than a collection of legs, ears, hair, and a wet nose flying over the grass? And why, when the dog knocks us over, do we know to blame the dog?

To put these questions another way: how do we group sensations into whole objects, and how do we decide that a certain set of perceptions constitutes cause and effect?

It's not a terribly easy problem to solve. The nature of causality isn't transmitted in an easy-to-sense form like color is in light. Rather than sense it directly, we have to gues. We have built-in heuristics to do just that, and these heuristics are based on various forms of togetherness. The word "this" hangs together well because the letters are in a straight line, for example, and they're closer to one another than the letters in the surrounding words. Those are both principles by which the brain performs grouping. To take the second question, we see the parts of the dog as a single animal because they move together. That's another heuristic.

This recognition acuity lets us see human forms from the tiniest of clues, but it alsoas we'll see in [Hack #77] is not perfect and can be duped. We'll see how we can perceive animacythe aliveness shown by living creatureswhere none exists and how we can ignore the cause in cause and effect. Sometimes that's the best way to find out what our assumptions really are, to see when they don't quite match what's happening in the real world.