842 THE POPULAR SCIENCE MONTHLY. 



cuius of reasoning had, at different times, occupied Boole's thoughts, 

 but it was not till the spring of 1847 that a memorable logical con- 

 troversy led him to put his ideas into a definite form. He afterward 

 regarded this pamphlet as a hasty and imperfect exposition of his logi- 

 cal system, and desired that his much larger work, " An Investigation 

 of the Laws of Thought," etc. (1854), should alone be considered as 

 containing a mature statement of his views. 



This is Boole's greatest work, and is an attempt to apply the sym- 

 bols and operations of mathematics to logic and the laws of thinking. 

 The object of the work, as stated by himself, is "to investigate the 

 fundamental laws of those operations of the mind by which reasoning 

 is performed ; to give expression to them in the symbolical language 

 of a calculus, and upon this foundation to establish the science of 

 logic and construct its method ; to make that method itself the basis' 

 of a general method for the application of the mathematical doctrine 

 of probabilities ; and, finally, to collect from the various elements of 

 truth, brought to view in the course of these inquiries, some probable 

 intimations concerning the nature and constitution of the human mind." 



Of this work Professor Todhunter, in the preface to his "History 

 of the Theory of Probabilities," speaks as "marvelous" ; and, in simi- 

 lar language, Professor W. Stanley Jevons speaks of it as " one of the 

 most marvelous and admirable pieces of reasoning ever put together." 



It is often supposed that mathematicians are deficient in judgment 

 and knowledge of other matters. In Boole this was not the case ; 

 for, though he published little except his mathematical and logical 

 works, his acquaintance with general literature was wide and deep. 

 Dante was his favorite poet, and he preferred the "Paradiso" to the 

 " Inferno." The metaphysics of Aristotle, the ethics of Spinoza, the 

 philosophical works of Cicero, and works of a kindred character, Avere 

 frequent subjects of his study. 



The pei - sonal character of Boole inspired all his friends with the 

 deepest esteem. He was marked by the modesty of true genius, and 

 his life was given to the single-minded pursuit of truth. Though he 

 received a royal medal for his memoir (" Philosophical Transactions of 

 the Royal Society," 1844), and the honorary degree of LL. D. from 

 the University of Dublin, it may be said that he neither sought nor 

 received the ordinary rewards to which his discoveries entitled him. 



" On the 8th of December, 1864, in the full vigor of his intellectual 

 powers," says W. Stanley Jevons, in his tribute to his friend's life and 

 genius, " George Boole died of an attack of fever, ending in suffusion 

 on the lungs." 



The mathematical and logical works of Boole are by far too ab- 

 struse to admit of their being used as text-books in schools of even the 

 highest grades ; but as works of reference they are invaluable to ad- 

 vanced students and the special cultivators of pure mathematics and 

 the profounder problems of logic. 



