"There is an important lesson in this. All so-called pseudoscientists believe they are simply scientists, albeit ones with heterodox views marginalized by the mainstream. (They aren't necessarily right—many people have mistaken self-conceptions.) But to be a scientist, you need to behave like one, and one thing scientists do constantly is, well, demarcate. Velikovsky and his peers knew there was an edge to legitimate science, and they policed it very carefully, just like "establishment" scientists did and continue to do. I have come to think of pseudoscience as science's shadow. A shadow is cast by something; it has no substance of its own. The same is true for these doctrines on the fringe. If scientists use some criterion such as peer review to demarcate, so will the fringe (creationists have peer-reviewed journals, as did Velikovskians). The brighter the light of science—that is, the greater its cultural prestige and authority—the sharper the shadow, and the more the fringe flourishes."