Notes, i. I. 141 



NOTES. 



BOOK I. 



(Ch. 1.) 1. A similar view of education, as embracing a knowledge of the methods of 

 sciences, and making its possessor a competent judge of the performance of scientific 

 professors as regards method and the degree of precision which may be expected from 

 • them in each science, is to be found in several passages [e.g. Pol. iii. i r ; N'. Eth. i. i). In 

 the former of these passages three degrees or kinds of knowledge seem to be recognised in 

 each science. In medicine, for instance, there is the knowledge of {practice, which 

 belongs to the empiric ; the knowledge of theory or method, which belongs to the 

 man of education ; and the knowledge of practice and of theory combined, which 

 belongs to the scientific physician. Besides this distinction as to the quality of knowledge, 

 there is further a distinction as to its extent ; for it may be limited to one science or 

 embrace them all. 



2. A. employs only two formal terms of classification, species («l5oj) and genus {-yhoi). 

 Of these the former is practically defined by him {H. A. i. I, 4) as "an assemblage of 

 individuals in which not only the whole form of any one resembles in all essential points 

 the whole form of any other, but each separate part, internal and external, similarly 

 resembles the corresponding part in any other." This definition scarcely differs from that 

 of Cuvier : " Chaque corps organise, outre les qualites communes de son tissu, a une 

 forme propre, non seulement en general et \ I'exterieur, mais jusque dans le detail de la 

 structure de chacune de ses parties " {Regne An. i. 14) ; and " tous les etres appar- 

 tenants k I'une de ces formes constituent ce que I'on appelle une espece" {do. p. 16). A.'s 

 fiSos may then as a rule be fairly translated species. The other term (^eVos) is used 

 much more vaguely. It is described by him as " an assemblage of individuals, all of 

 which bear an obvious resemblance to each other, but which do not belong to one and 

 the same species, inasmuch as their corresponding parts are not precisely similar, but 

 differ usually in colour, shape, or proportion. Sometimes even one has some parts that 

 are not represented in another. Thus Birds and Fishes each form a genus, containing 

 numerous species" {H. A. i. i, 5 — 8). Again, "there are other groups of animals, in 

 which the difference between the corresponding parts is still greater ; the only resem- 

 blance being that of analogy, as between a scale and a feather ; a scale being to a fish 

 what a feather is to a bird " (^ff. A. i. I, 9). Such groups are too wide asunder to be 

 united into one genus (Z>. P. i. 4, 2). Putting these several passages together, we have 

 a tolerably clear definition of genus ; and, judging from the examples, it may mean any 

 natural group of animals larger than a species and not larger than a class. The class 



