Have you noticed how even after tidying up your bedroom it somehow manages to become untidy again? Which would you say is the natural state- messy or tidy?
A tidy bedroom is the natural state as the mess has been artificially created by yourself.
Our minds work much in the same way. We've created many habit patterns that we perceive to be natural when in actual fact, we've placed these patterns there ourselves and now operate under their command. Like placing a big pile of clothes on the bedroom floor, walking around it and thinking this is normal.
Meditation is the process of mental purification. It is the removal of habit patterns that have been placed by ourself. Once we have removed all habit patterns, we come back to our true nature.