Reason

Reason was a logical method of decision making. Borusa wrote a paper on the topic which the Doctor had read. When Rodan told her that it suggested the Fourth Doctor was a traitor, Leela replied that "reason [was] a liar". (TV: The Invasion of Time)

The Twelfth Doctor suggested more than once that instead of steering the TARDIS, he had to reason with it, (TV: Smile) "unsuccessfully most of the time". (TV: Thin Ice)