A fly passes in front of a frog's visual field. The frog's tongue flicks at the fly and brings it into its mouth. We watch this display and marvel at the frog's ability, something we can't do. We marvel at the fact that the frog knew wat the little black thing is front of it was a source of food, knew exactly when it where it was headed, and knew where to flick its tongue in order to capture and eat it. Where did it store the information it needed to do this neat trick? In its neural circuitry, of course. But how did its neural circuits attain the ability to store this information?

The answer: natural selection. In the evolutionary past, there was strong selection for genes that build nerve circuits in the visual system that are stimulated to fire just by little black moving dots in the frog's visual field. Big dots won't do it, nor will motionless little ones. The advantage of such circuits is obvious. The only moving little black dots in the frog's environment are insects it can eat. There was also selection for (genes that build) other circuits wired to take an inputs the visual system's output and send their own output to other neural circuits that ultimately trigger tongue flicking. The process was just blind variation and environmental filtration. Over the evolutionary history of frogs, variation resulted in a few neural circuits connected to the eyes and the tongue in ways that happened to result in eating; most didn't. the ones that did were selected for. There is nothing special about these neural circuits or different from other neural circuits that can do this job, other than their fortuitously connecting circuits from the eye to circuits for the tongue. These neurons aren't any more about the fly than others that could do the same job but don't because they are hooked up to other circuits. Frogs aren't smart enough to learn how to flick flies by operant conditioning. Their survival is a testimony to how finely Mother Nature (aka genetic natural selection) can tune the appropriateness of responses to the environment.

We are of course, amazed at the environmental appropriateness of the frog's tongue flickering. We say, "The frog knows where the fly is. There must be neurons in its brain that contain information about the fly's speed and direction." It's perfectly natural for us to say this, but it's an illusion that results solely from the environmental appropriateness of the dot-detection to tongue-flicking chain of natural inputs and outputs. The frog's neural circuitry can't be about the fly; they can't be about anything. So, when we say that there are neural circuits in the frog that acquire information about flies, store this information, and make use of it to stimulate, direct, or control tongue flicking, we are either speaking metaphorically or we have succumbed to an illusion. ~ Page 197