The two nations theory would appear as an untenable idea if analysed critically. The gist of the theory is that Hindus and Muslims are two different nations and religions and they, therefore, can not live together. Muslim Leagues' support for partition was based solely this theory. But the real causes of partition were altogether different from two nations theory. The real causes were political, economical and other social factors, like the fear of Hindu dominance over minority muslims.
The two nations theory fails to satisfy an unbiased and reasonable mind. It is to say that Muslims ruled over Hindus and sub-continent for centuries but they never thought of separating themselves from Hindus on the ground that the two nations are altogether different and therefore they can not live together.
Muslims enjoyed ruling over Hindus for centuries and when they were no longer the masters of the subcontinent, they feared Hindu rule. This fear was compelled the Muslims to safeguard their interests. For this, the Muslim leaders needed the support of the masses which they could not attract in real sense. Then dragging of religion in politics was a tactic to win masses' support.
Even after partition the population was of Muslims in the two countries was equal. So the conclusion is that economic and social differences outweigh the religious differences. Economic and social factors were the main causes of partition rather than two nations.
Why the two nations theory could not preclude the East Pakistan from going for separation? East and West Pakistan formed a nation according to two nations theory but economic and social factors separated the same nation that came into being on two nations theory.