Intellectual Incest

Defined:

Intellectual Incest is a situation where too many people in a group all think alike and exclude legitimate diverse viewpoints. Not all points of view are intelligent arguments but sometimes when people become too uniform, they fail to evolve for lack of fresh new ideas. The concept is similar to genetic inbreeding. Realists are encouraged to exchange ideas with people who are not of the same mindset because it gives both individuals the opportunity to learn something new. When people hang out with people who agree on everything then there is less opportunity to learn from a new point of view and it leads to stagnation.

Visit a trad or neocon discussion forum (or blog combox) sometime; almost always you will find there the sickly or even deformed mental fruits of such intellectual inbreeding.

This is also a huge part of why I find the "enclosed monastic hothouse" of the seminaries to be a huge turn-off (and very creepy).