418 The Evolution of Scientific Knowledge, [July, 
of a hitherto unrecognised planet, and recommended M. 
Galli, of the Berlin Observatory, to diredt his telescope, on 
the 23rd September, to a definite point in the heavens : he 
did so, and beheld the planet Neptune. Here, then, was 
exadt quantitative prevision. In the last of these examples 
we see science completely differentiated from common know- 
ledge. In the first we see science scarcely differentiated from 
common knowledge. The child who having been burnt 
dreads fire exhibits qualitative prevision, but it can scarcely 
be said that his knowledge is science. And this serves to 
show how difficult it is to separate common knowledge from 
incipient science. Looking at the question then in this 
general way, there can, I think, be no doubt that the passage 
of the general mass of knowledge into science exemplifies 
evolution. In the separation of the special sciences from 
each other we have a clear case of differentiation ; in the 
growing inter-dependencies of the sciences (to be more parti- 
cularly noticed presently) we have a further trait of evolu- 
tion ; while daily integrations of our knowledge tend more 
completely to fuse the body of scientific knowledge into a 
definite complex whole. 
Let us now turn to more special examples. 
It is probable that in very early times men were led to 
speculate on the constitution of that starry firmament which 
night after night met their gaze. What may have been the 
exadt nature of the views which were the outcome of this 
primitive guessing we shall probably never know, but we 
may form some idea by enquiring what are the views of the 
uncivilised to-day. We find, on doing so, that the South 
Australians think “ the constellations are groups of children,” 
and “ three stars in one of the constellations are said to have 
been formerly on the earth : one is the man, another his 
wife, and the smaller one their dog ; and their employment 
is that of hunting opossums through the sky.” We find, 
too, that the Esquimaux think the sun, moon, and stars are 
“ spirits of departed Esquimaux, or of some of the lower 
animals.” We find again— but we need go no further. 
Little is to be learnt from these guesses ; but we may fairly 
suppose that it was long ere vague mythological ideas gave 
place to conceptions based on physical analogies. Among 
the early Greeks, however, the phenomena of the heavens 
were, according to Whewell, explained on the. supposition 
that the sky is a concave sphere or dome, to which the stars 
are fixed, and that the celestial sphere revolves perpetually 
and uniformly about the pole or fixed point. Here, then, 
we have an explanation in some sort physical, but one of 
