xxx.] CLASSIFICATION. 703 



illustrating those predicables, which constitutes a good 

 specimen of bifurcate classification. Translating his words l 

 freely we may say that he takes Substance as the genus to 

 be divided, under which are successively placed as Species 

 Body, Animated Body, Animal, Eational Animal, and Man. 

 Under Man, again, come Socrates, Plato, and other parti- 

 cular men. Now of these notions Substance is the gemis 

 generalissimum, and is a genus only, not a species. Man, 

 on the other hand, is the species specialissima (infima 

 species), and is a species only, not a genus. Body is a 

 species of substance, but a genus of animated body, which, 

 again, is a species of body but a genus of animal. 

 Animal is a species of animated body, but a genus of 

 rational animal, which, again, is a species of animal, but a 

 genus of man. Finally, man is a species of rational animal, 

 but is a species merely and not a genus, being divisible 

 only into particular men. 



Porphyry proceeds at some length to employ his example 

 in further illustration of the predicables. We do not 

 find in Porphyry's own work any scheme or diagram 

 exhibiting this curious specimen of classification, but some 

 of the earlier commentators and epitome writers drew what 

 has long been called the Tree of Porphyry. This diagram, 

 which may be found in most elementary works on Logic, 2 

 is also called the Eamean Tree, because Eamus insisted 

 much upon the value of Dichotomy. With the exception 

 of Jeremy Bentham 3 and George Bentham, hardly any 

 modern logicians hove shown an appreciation of the value 

 of bifurcate classification. The latter author has treated 

 the subject, both in his Outline of a New System of Logic 

 (pp. 105-118), and in his earlier work entitled Essai sur la 

 Nomenclature et la Classification des Principales Branches 

 d'Art-et-Science (Paris, 1823), which consists of a free 

 translation or improved version of his uncle's Essay on 

 Classification in the Chrestomathia. Some interest attaches 

 to the history of the Tree of Porphyry and Eamus, because it 

 is the prototype of the Logical Alphabet which lies at the 

 basis of logical method. Jeremy Bentham speaks truly 



1 Porphyrii Isagoge, Caput ii. 24. 



2 Jevons, Elementary Lessons in Logic, p. 104. 



3 ChrettQmathia ; being a Collection of Papers, &c. London, 1816, 

 Appendix V. 



