Ignorance is the failure to discriminate between the permanent and the impermanent, the pure and the impure, bliss and suffering, the Self and the non-Self.
Yoga is the settling of the mind into silence. When the mind has settled, we are established in our essential nature, which is unbounded Consciousness. Our essential nature is usually overshadowed by the activity of the mind.
The cause of suffering is that the unbounded Self is overshadowed by the world.
Knowledge born of the finest discrimination takes us to the farthest shore. It is intuitive, omniscient, and beyond all divisions of time and space.