Food for thought: Renewing your mind

From Miracles: How God Intervenes in Nature and Human Affairs by C.S. Lewis:

Your rational thinking has no foothold in your merely natural consciousness except what it wins and maintains by conquest. The moment rational thought ceases, imagination, mental habit, temperament, and the “spirit of the age” take charge of you again. New thoughts, until they themselves become habitual, will affect your consciousness as a whole only while you are actually thinking them. Reason has but to nod at his post, and instantly Nature’s patrols are infiltrating.