The senses, concepts, logic: these are the elements of man’s rational
faculty—its start, its form, its method. In essence, “follow reason” means:
base knowledge on observation; form concepts according to the actual
(measurable) relationships among concretes; use concepts according to the rules
of logic (ultimately, the Law of Identity). Since each of these elements is
based on the facts of reality, the conclusions reached by a process of reason
The alternative to reason is some form of mysticism or skepticism.