A fluid mind will always bring rational thought to bear on beliefs. Beliefs should be fluid entities within the mind, some more certain and viscous, others doubtful and mutable. A fluid mind never feels so certain of a belief that it loses its fluidity. When a belief solidifies, it becomes like a shackle on the mind, inhibiting exploration, learning and growth. A fluid mind never allows a belief to be so hardened that it is beyond rational scrutiny.