Ignorance is the cause of egoism, attachment, aversion, and clinging to life. These impressions exist in different states. They are sometimes dormant. You often hear the expression "innocent as a baby," yet in the baby may be the state of a demon or of a god, which will come out by degrees. In the Yogi, these impressions, the Samskaras left by past actions, are attenuated, that is, exist in a very fine state, and he can control them, and not allow them to become manifest. "Overpowered" means that sometimes one set of impressions is held down for a while by those that are stronger, but they come out when that repressing cause is removed. The last state is the "expanded," when the Samskāras, having helpful surroundings, attain to a great activity, either as good or evil.