1. NATURE OF LOGICAL DIVISION.
The term genus is used for any class name which stands for two or more subordinate classes while the term species is made to stand for any one of the subordinate classes.
The proximate genus of any species is the next class above. For example the proximate genus of man is biped, not animal.
Logical division is the process of separating a proximate genus into its co-ordinate species.
ILLUSTRATIONS:
| Genus | Species | |
| (1) Heavenly bodies |
Fixed stars Planets Satellites Comets Meteors Nebulae | |
| (2) Vertebrates |
Leptocardians Fishes Amphibians Reptiles Birds Mammals | |
| (3) Man |
Caucasian Mongolian Malay Ethiopian American Indian | |
| (4) Government |
Monarchy Aristocracy Democracy |