Form and content – two levels of change
Your Brain Is Not Your Liver
It is easier to be aware of the content level in a given circumstance because we give such a large portion of our attention to our thoughts, but not to the thinking activity that produced them. Thoughts, as the embodiment of difference, act as a natural attractor for our attention, which is keyed to difference in general. This principle is even embedded systemically into our very physiology: all our senses are built on maximizing differences. Our visual sense, for example, relies upon specialized areas of the brain devoted to detecting specific types of difference, such as contrast or movement. But the principle is even more general; the very functioning of the nervous system as a whole can be described as the integrated control of depolarization waves (differences traveling through the axons of the nerves).
It is accurate to say that in general, the nervous system (the basis of thinking physiologically) is more keyed to differences than other aspects of our physiology. A smaller difference in the nervous system can have a greater effect (a greater difference) than a similarly scaled difference in the rhythmic or metabolic systems. This is why we can pinpoint the relationship between smaller and smaller areas of the brain and specific experiences, even to individual neurons. Think of the activity of the liver for contrast: this organ is so resilient that it can still function if half of its tissue is gone, and can regenerate itself fully given time. Indeed this is regularly practiced in live-donor liver transplants. But the brain is so specialized (attuned to difference) that a corresponding transplant of the brain would result in catastrophe.