The Expression of the Enlightenment Attained by the Prophets Reason is based on perception, conviction, and motivation. Reason changes when all these constituents change. If the mind is purely guided by reason, motivation alone can confuse it, and cloud the judgment because of the inherent instability of reason.
Reason makes the mind most unstable.
When attachment arises, wisdom is shut out. What denies freedom to the mind is the dead-weight of reason. For clarity of thought, the mind must be impartial. Clarity of thought is very much essential because action is motivated by it. This is true of reasoning at all levels- individual, social, political, national, etc.