EVOLUTION OF THE UNIVERSE. 601 
million years ago. If the theory be true, planetary systems.must be rare 
and therefore consciousness, as men know and possess it, is rare. In fact, 
the existence of consciousness, when it occurs, will be the by-product of 
an accident. We are then apparently forced to conclude that the universe 
was not created with the primary object of producing beings in whom mind 
should lead to spiritual excellence. 
There is, of course, no reason why consciousness should be associated 
with animals such as ourselves who represent transformations of carbon 
compounds at temperatures between the boiling and freezing points of 
water. It might, for all we know to the contrary, be associated with 
changes in the ionisation of atoms or with the disintegration of their 
nuclei at temperatures of hundreds of millions of degrees. But of any 
such bases for the appearance of mind we have no knowledge. What we 
do know with certainty is that throughout the universe the raw material 
of which it is made is fairly uniform. The matter in distant stars is the 
same as that which exists in our own sun. We must then assume that 
there are planetary systems in distant island nebulae, and that on some 
of them conditions resemble those which exist on our earth. So life, as 
we know it, must be distributed throughout the universe; but, if the 
collision theory of planetary origins is correct, the distribution is 
astonishingly sparse. 
I do not, of course, suggest that there are human beings on other 
planets. The direction of the physical and physiological evolution of 
living things upon our earth would seem, if we can judge by the geological 
record, to have been somewhat erratic. Particular mutations coincided 
with particular conditions of environment to determine the direction of 
change at any instant. But, throughout the known geological process 
there has been large-scale progress, a possibly unsteady but quite definite 
development of mind. In the possibly very different living organisms of 
other planets there will have been a progressive development of mind. 
Our physical structure matters little in comparison with the kind of 
consciousness which it carries. 
We can then, as it seems to me, assume the existence throughout the 
universe of conscious beings. If it be true that our earth and all planetary 
systems similar to our own originated in a chance collision of suns, life 
elsewhere must be as a rule unimaginably more developed than with 
ourselves. Also planets carrying living organisms must be incredibly 
rare. After a life history of five million million years our galactic universe 
will have but one sun in a hundred thousand with satellites which can 
earry life. Such extravagant world-building for such meagre results 
leaves one dubious as to whether the theory is correct. In defence of such 
doubts as are forced upon me I might point out that the origin of our 
moon, with its exceptional density and massiveness, has not been finally 
settled. The theory that it was broken from the earth when the latter 
was mainly liquid owing to a chance ‘ resonance’ phenomenon Jeffreys, 
in a recent paper, deems untrue. Even present estimates of the age of 
the earth, in so far as they depend on the rate of disintegration of uranium, 
puzzle us because we do not know why there should have been any 
uranium in the earth at its birth. Thus I, personally, should not be 
surprised if new facts were forthcoming to give some other explanation 
