LATER PHASES IN MENTAL DEVELOPMENT 57 
We are thinking about colour, which is both abstract and 
general—abstract, because in itself it is a special quality of 
visible objects floated off, so to speak, from other qualities, 
such as hardness and weight, shape and size; general, because 
it includes many different colours in one group. Looking up 
at the bookshelves, we see a volume with a red back. We 
neglect the shape, the contents, the lettering ; it is the colour 
with which we are immediately concerned, which forms an 
important feature in the present thought-situation ; and this 
is, in virtue of that situation, abstracted from the rest. But 
a chick a few days old may have acquired experience of several 
kinds of caterpillars much alike in shape and size ; of which, one 
kind is ringed with orange and black. And while the others 
are eagerly seized, caterpillars of this kind are left untouched. 
It is not the size or the shape which is an effective element in 
the situation ; it is the peculiar coloration of the cinnabar 
caterpillars. Now, does the effectiveness of this quality in 
the stimulus justify the inference that the chick forms an 
abstract idea of colour? That clearly depends on our defini- 
tion of abstract idea, and on our inferences concerning the 
nature of the chick’s mind. 
A dog lies dozing upon the mat, and hears a step in the 
porch without. His behaviour at once shows that this enters 
into the conscious situation. There is, moreover, a marked 
difference according as the step has the familiar fall of the 
master’s tread, the well-known shuffle of the irrepressible 
butcher’s lad, or an unfamiliar sound. These several situations 
are, without question, nicely distinguished. Let us suppose 
the situation of the moment is introduced by a. strange foot- 
fall. It seems to suggest man ; but this cannot be any parti- 
~ cular man, since he is as yet invisible and is a stranger. Does 
the dog, then, frame a general idea of man ? Does the chamois 
do so when, bounding across the snow field, he stops suddenly 
on scenting the distant footprints of a mountaineer ? Do you 
do so when you hear the bleating of an invisible lamb in the 
meadow behind yonder wall? Here, again, the answers we 
give to these questions depend partly on the exact meaning 
