1) An idea whose reasonableness is inversely proportionate to the size and diversity of the community harboring it.
2) An epistemological glut of homogeneity.
Three white, heterosexual, property owning males are 100% sure that the system they have devised is the best way to run a civilization. As they set out into society to build support for that system, the diversity of their group grows, and the reasonableness of the system begins to falter. Their idea was an epiglut. It only holds water if they exclude membership to similar minded people, and deny the existence of communities that refute it.