Reason

The Buddha's authority with his students was not that of one who imposes his views on another. The Buddha consistently debated with and persuaded those with whom he was speaking through the use of reason. Because his concern was to change the way people live, his reason was practical rather than theoretical.

The Buddha used reason to help others decide how to think, to speak, and to act. He had no interest in pursuing an abstract argument to demonstrate a purely theoretical truth.

The Buddha's practical reason was ethical.

The Buddha's first principle could be stated:

                  Do no evil,
                  Take up what is good,
                  Purify the mind—
                  This is the teaching of the buddhas.

                                       ---The Dhammapada 183---