“The more wisdom you attain and the more conscious you become, the crazier you will appear to others.” —Anonymous
This is easily explained by the fact that intelligence naturally has a normal, “bell curve” distribution. The few highly intelligent people are able to understand each other, but may appear crazy (or even dumb) to the general population who are not able to understand them.
The main reason many highly intelligent people are not actually regarded as crazy is because they have managed to acquire a good reputation for themselves through practical, real-life achievements, in addition to the fact that most of them seem able to understand each other.
However, in the world of Philosophy, Religion, Economics, Social Sciences, etc., things get really murky, because there is often no practical, real-life achievement—specifically, achievements that directly demonstrate their level of expertise—to go with whatever reputation that thinkers in those fields have managed to acquire / amass.
Which is why in those fields, the popular, “main stream” view is actually quite unlikely to be the most intelligent view available. Simple statistical analysis tells us that the most intelligent view is probably shared by the few highly intelligent people at the top end of the intelligence spectrum (i.e. the “bell curve”).
P.S. the practical implication of this knowledge is that everyone has the responsibility to try to educate themselves, and in so doing lift up the average, no matter where in the “bell curve” they actually are. And of course try not to overestimate their own competence, which means being open to the fact that there are people out there more intelligent than us from whom we have much to learn.