ABSTRACT
Synopsis The Essays on the Intellectual Powers ends with a vitally important chapter containing Reid’s theory of the faculty of reason and his account of the sources of human error. An information processing model shapes the discussion. The irresistible beliefs arising from the senses are the output of various input systems or perceptual faculties responding automatically to signs interpreted by innate principles. These faculties may yield error if they malfunction or are used in circumstances for which they were not intended, but otherwise they yield truth. If they did not, since the output is irresistible, error would be unavoidable. When we go beyond these faculties or input systems to the level of reason or the central system, whether we err or reach the truth will depend on how well we reason. This is a higher level of ratiocinative processing of information than the first-level automatic response to signs. We may avoid error in ratiocination with the use of the proper methods or fall into error with the use of fallacious ones.
