Artificial classifications are resorted to for some special purpose, designed by man, not by nature. Consequently artificial classifications are sometimes called _special_ or _working_ classifications.
_A natural classification is one in which the grouping is made on the basis of some inherent mark of resemblance._
Classifications in animal and plant life are the best illustrations of this kind. Such classifications are suggested by nature and not by man, and may, therefore, be called _general_ or scientific. The main aim of natural classification is to derive general truths and arrange knowledge so that it may be easily remembered.
The rules of logical division are applicable in the making of a logical classification. In addition to these an artificial classification should be made to conform to the one rule: _The classification must be appropriate to the purpose in hand._ Likewise a natural classification should be made to conform to the rule: _Every classification should afford opportunity for the greatest possible number of general assertions._
=9. USE OF DIVISION AND CLASSIFICATION IN THE SCHOOL ROOM.=
It has been stated that classification and division aim at the same result. Classification reduces multiplicity to unity while division differentiates unity into multiplicity. In short, division is _deductive_ while classification is _inductive_ in mode of procedure. Therefore, classification should be used in those situations which call for induction and division in cases where deduction is the better method.
Speaking generally, classification should be used with small children when the essential thing is to present the concrete facts with a view of leading the children to discover for themselves the truths contained therein.
With older pupils division may be used, if the purpose is to set in order facts which are already known.
(1) Nature of Logical Division. Genus――species. Illustrations.
(2) Logical Division Distinguished from Enumeration. Illustrations.
(3) Logical Division and Partition. Quantitative――qualitative. How summarized.
(4) Four Rules of Logical Division. (1) One principle――cross division. (2) Mutually exclusive. (3) Exhaustive――complete. (4) Immediate species.