120 READINGS IN EVOLUTION, GENETICS, AND EUGENICS 
that upon their results must be built synthetic studies, if taxonomy 
is to fulfil its purpose. 
THE METHOD OF CLASSIFICATION 
CHARLES DARWIN’ 
Naturalists, as we have seen, try to arrange the species, genera, 
and families in each class, on what is called the Natural System. But, 
what is meant by this system? Some authors look at it merely as a 
scheme for arranging together those living objects which are most 
alike, and for separating those which are most unlike; or as an artificial 
method of enunciating, as briefly as possible, general propositions,— 
that is, by one sentence to give the characters common, for instance, 
to all mammals, by another those common to all carnivora, by another 
those common to the dog-genus, and then, by adding a single sentence, 
a full description is given of each kind of dog. The ingenuity 
and utility of this system are indisputable. But many naturalists 
think that something more is meant by the Natural System; they 
believe that it reveals the plan of the Creator; but unless it be specified 
whether order in time or space, or both, or what else is meant by the 
plan of the Creator, it seems to me that nothing is thus added to our 
knowledge. Expressions such as that famous one by Linnaeus, which 
we often meet with in a more or less concealed form, namely, that the 
characters do not make the genus, but that the genus gives the charac- 
ters, seem to imply that some deeper bond is included in our classifica- 
tions than mere resemblance. I believe that this is the case, and that 
community of descent—the one known cause of close similarity in 
organic beings—is the bond which, though observed by various 
degrees of modification, is partially revealed to us by our classifications. 
Let us now consider the rules followed in classification, and the 
difficulties which are encountered on the view that classification either 
gives some unknown plan of creation, or is simply a scheme for 
enunciating general propositions and of placing together the forms 
most like each other. It might have been thought (and was in ancient 
times thought) that those parts of the structure which determined the 
habits of life, and the general place of each being in the economy of 
nature, would be of very high importance in classification. Nothing 
can be more false. No one regards the external similarity of a mouse 
to a shrew, of a dugong to a whale, of a whale to a fish, as of any 
«From The Origin of Species. 
