Gary R. Kirby and Jeffrey R. Goodpaster work from the premise that good thinking is not exclusive to any one discipline. Their comprehensive approach to the study of critical thinking draws on philosophy, literature, the natural sciences, psychology, and from many periods of history; from Aristotle, who notes that we are only "apparently rational" to Antonio Damasio, the contemporary brain researcher, who cautions, "the brain is just like a muscle-use it or lose it." The range of Thinking makes it the preeminent interdisciplinary text.