CHAPTEK XXW 
ON SPECIES 
Illustrations of the way in which Hooker's own conceptions 
of species and their problems took shape may be drawn from 
his correspondence during this period. He viewed the question 
from two sides, for he was the shining exception who gave 
point to Darwin's complaint : ^ 
How few generahsers there are among systematists. 
I really suspect there is something absolutely opposed to 
each other and hostile in the two frames of mind required 
for systematising and reasoning on a large collection of 
facts. (CD. ii. 39,) 
His mind was scientific in both the wider and the narrower 
sense. It combined observation with generalisation, the need 
for orderly detail with the equally impelling need for principles 
to give these ordered details an intelligible interpretation. 
The primary object of science is order, and order is expressed 
by classification. A perfect classification seeks its basis in 
all the criteria gradually brought to light by research. Collec- 
tion, labelling, grouping by external likeness is not enough. 
Each advance in scientific order expresses more truly the 
inner workings of nature, and to improve classification, there- 
fore, is of more vital importance than to add to the store of ac- 
cumulated material. Thus a group given individual importance 
on inadequate grounds became an offence against science, and 
obscured yet further the dark question of the origin of species. 
To reason on the ill-defined was hopeless. And so ill-defined 
1 See further, vol. ii. pp. 18, 26-31 ; Essay on the Distribution of Arctic Plants 
465 
