An introductory text-book of logic - Mellone, Sydney - Rare Books at ...

DEFINITION. 185
The celebrated Linnsean system of classification in Botany
is an example of one which, though made for scientific pur
"
poses, is not natural." He took as his basis of classifica
tion the numbers of the sexual parts of the plants, the pistils
and stamens, as a clue to natural affinities. They are in
and some of his
deed an important means of identification ;
classes coincide with classes in the "natural" system of
division ; but his classification is not natural because it goes
on the one principle of number. The history of botanical
classification on which the student may consult any stand
ard text-bookis the best example of the attainment of a
natural system of classification.
It scarcely needs to be said that all natural classifi
cation and all classification for scientific purposes,
whether natural or not, depends entirely on our know
ledge of Nature s processes and objects. The detailed
rules of classification depend on the special character
istics of that part of Nature with which the science
deals. All that Logic can do is to give a general
account of the process which all science employs, in
arranging its objects so as to throw as much light as
possible on their origin, structure, and affinities.
We have seen that a classification may be "natural,"
having as a basis the most fundamental or essential
qualities, from which the largest number of others are
derived ; or it may have as a basis those characteristics
which merely accompany the largest number of others.
In both cases, the basis of the classification consists of
numerous common qualities taken together ; and both
may be accounted "natural" classifications, using the
term in a slightly wider sense than we did before. But
we saw also that even in science, classifications are
often made on the basis of a single quality, for the
sake of ready identification. Classifications of this
kind, made on the basis of a single attribute, or very
few attributes, are called artificial. Usually an artificial