GENERAL VIEW OF NATURE AND SCOPE OF LOGIC. 13 



the circumstances of the concrete problem before them, analyse 

 these circumstances and reconstruct and review them in a certain 

 order, to see how best to act in the particular case. Now this 

 kind of reflection results in the deliberate and reasoned formation 

 of a body of rules for the habitual guidance of the mind in those 

 operations of thought by which all our knowledge is acquired and 

 all our activities directed. And this body of practical rules con 

 stitutes what is called Artificial Logic. 



To have the art of doing a certain thing is simply to know 

 and possess and make use of all the requisite means for doing 

 that thing well and properly. &quot; An art,&quot; says St. Thomas, &quot; is 

 nothing more than a right conception of the way to do certain 

 things &quot;. * Logic, considered as an art, is therefore the collection 

 of those practical rules which should regulate our thinking and 

 reasoning processes. And as it is these latter functions which frame 

 the rules for all departments of external activity the rules which 

 constitute all the arts the art of right thinking will underlie and 

 direct all the other arts. For this reason logic is sometimes 

 called the Ars Artium, the art of arts. 2 And this is very intellig 

 ible ; for all conscious mistakes in any department of activity 

 whatever arise ultimately from errors of judgment, just as all 

 success in external activity is based upon rectitude or soundness of 

 judgment. 



To act well we must first of all judge well. But if we are to 

 judge well to form sound and true judgments we must make a 

 careful study of the materials of thought in order to see how they 



1 &quot; Ars nihil aliud est quam recta ratio aliquorum operum faciendorum.&quot; St. 

 Thomas, Summa Theol. i a 2a e , q. 57, art. 3, c. 



2 &quot; Alia animalia, ait, quodam naturali instinctu ad suos actus aguntur, homo 

 autem rationis judicio in suis operibus dirigitur. Et inde est, quod ad actus 

 humanos faciliter et ordinate perficiendos diversae artes deserviunt. Nihil enim 

 aliud ars esse videtur quam certa ordinatio rationis, qua per determinata media ad 

 debitum finem actus humani perveniunt. Ratio autem non solum dirigere potest 

 inferiorum partium actus, sed etiam actus sui directiva est. Hoc enim est proprium 

 intellectivae partis ut in seipsam reflectatur : nam intellectus intelligit seipsum, et 

 similiter ratio de suo agtu ratiocinari potest. Sicut igitur in hoc quod ratio de actu 

 manus ratiocinatur adinventa est ars edificatoria vel fabrilis, per quas homo faciliter 

 et ordinate hujusmodi actus exercere potest ; eadem ratione ars quaedam necessaria 

 est, quae sit directiva ipsius actus rationis, per quam scilicet homo in ipso actu 

 rationis ordinate et faciliter et sine errore procedet. Et haec est ars Logica, id 

 est rationalis scientia. Quae non solum rationalis est ex hoc, quod est secundum 

 rationem, quod est omnibus artibus commune ; sed etiam ex hoc, quod est circa ipsum 

 actum rationis sicut circa propriam materiam. Et ideo videtur esse ars artium ; quia 

 in actu rationis nos dirigit, a quo omnes artes procedunt.&quot; St. Thomas, i Post 

 Anal., lect. i. 



