For the matter of social unity, which can be a source of every joy and success, is practiced only between bodies, and bodily matters in people, and the separation between them is the source of every calamity and misfortune. But with matters of concepts and ideas, it is the complete opposite. That is to say, that because unity and lack of criticism is deemed the source of all failure and the greatest obstacle to every progress and didactic fertilization. For drawing the right conclusions depends mainly on the multiplicity of disagreements and separation, between opinions. The more contradictions there are between opinions and the more criticism there is, the more the knowledge and wisdom increase and matters become more suitable for examination.
The degeneration and failure of intelligence stem only from the lack of criticism and disagreement. For it is plain to see that every basis for physical success is the measure of the unity of society, and the basis for the success of intelligence and knowledge, is the separation and disagreement among them.
Courtesy of http://www.youtube.com/watch?v=1y4rDTzoEzI