The Commens Dictionary

Quote from ‘Logic’


… it is only the deliberate adoption of a belief in consequence of the admitted truth of some other proposition which is, properly speaking, reasoning. In that case the belief is adopted because the reasoner conceives that the method by which it has been determined would either in no analogous case lead to a false conclusion from true premisses, or, if steadily adhered to, would at length lead to an indefinite approximation to the truth, or, at least, would assure the reasoner of ultimately attaining as close an approach to the truth as he can, in any way, be assured of attaining. In all reasoning, therefore, there is a more or less conscious reference to a general method, implying some commencement of such a classification of arguments as the logician attempts. Such a classification of arguments, antecedent to any systematic study of the subject, is called the reasoner’s logica utens, in contradistinction to the result of the scientific study, which is called logica docens.

CP 2.204
‘Logica Utens’ (pub. 31.01.13-20:28). Quote in M. Bergman & S. Paavola (Eds.), The Commens Dictionary: Peirce's Terms in His Own Words. New Edition. Retrieved from
Jan 31, 2013, 20:28 by Sami Paavola
Last revised: 
Jan 07, 2014, 01:00 by Commens Admin