(2) “Logic is the science which investigates the process of thinking.” Creighton.
(3) “Logic as a science aims to ascertain what are the laws of thought; as an art it aims to apply these laws to the detection of fallacies or for the determination of correct reasoning.” Hyslop.
(4) “Logic is the art of thinking.” Watts.
(5) “Logic is the science and also the art of thinking.” Whateley.
(6) “Logic is the science of the formal and necessary laws of thought.” Hamilton.
(7) “Logic is the science of the regulative laws of the human understanding.” Ueberweg.
(8) “Logic treats of the nature and of the laws of thought.” Hibben.
(9) “Logic may be defined as the science of the conditions on which correct thoughts depend, and the art of attaining to correct and avoiding incorrect thoughts.” Fowler.
(10) “Logic is the science of the operations of the understanding which are subservient to the estimation of evidence.” Mill.
(11) “Logic may be briefly described as a body of doctrines and rules having reference to truth.” Bain.