598 DISCUSSION ON THE 
Rt. Rev. the Lorp BisHop oF BrruincHam, F.R.S. 
I will begin by briefly recapitulating the theory of the evolution of the 
universe in the form in which, as I understand, it at present exists. 
In the beginning a large unbounded finite three-dimensional universe 
with space of very small positive curvature was filled with highly diffused 
matter of very small density. The matter began to aggregate into masses 
of approximately equal size, spread fairly uniformly throughout the space ; 
and the whole space began, at some epoch or another, to expand. The 
masses attracted neighbouring matter and somehow acquired velocities 
of rotation which increased as the matter in them condensed. Finally, 
incredibly vast bun-shaped aggregates, spinning too quickly for the 
stability of their outer edges, began to throw off drops, as it were. The 
drops congealed into suns, and ultimately the aggregates became the 
spiral nebulae which now exist. Each of them, apart from possible central 
regions of diffuse matter, consists of thousands of millions of stars. Our 
sun is a star of no particular importance, belonging to a spiral nebula or 
group of nebulae called the Galactic universe. That universe came into 
existence some five million million years ago. 
Since they first existed, stars in the various universes have moved 
aimlessly under the influence of their initial velocities and mutual attrac- 
tions. Periodically, but rarely, at intervals of tens or hundreds of millions 
of years, collisions between suns in the various universes have taken place 
and planetary systems have been born. So the earth came into existence 
some two or four thousand million years ago. Thus ours is quite possibly 
one of the youngest planetary systems in our universe. On the cooling 
earth primitive forms of life appeared at least a thousand million years 
ago; and gradually, by a slow evolution, more highly developed living 
organisms arose. Finally, about a million years ago sub-men emerged 
from a group of anthropoid apes. 
If I personally am critical of this picture, I plead that we must not 
confuse speculative possibility with satisfactory demonstration. I am 
concerned that we do not give arguments to obscurantists, who claim that 
the scientific theories of one generation are usually repudiated by the — 
next. So I would begin by emphasising that in the group of possibilities 
and probabilities just outlmed there is much less certainty than, say, in 
the facts upon which Darwin rested his conclusions when the Origin of 
Species was published seventy-two years ago. 
I need not refer to the prejudiced opposition by which Darwin was 
assailed. Of course, his triumph has been signally complete. But others 
before him had put forward theories of the evolution of terrestrial animals. 
What Darwin did was so to accumulate and arrange biological facts, that 
experts were convinced that evolution by the mechanism of natural 
selection had produced from primal organisms the vast range of living 
things upon the earth, including man himself. Since Darwin wrote, 
further investigation and discovery have confirmed his insight. Some of 
his subordinate opinions were erroneous; but his main scheme stands 
intact because his facts were correct. All fresh geological and embryo- 
logical investigation confirms the conclusions on which he rested. The 
scanty remains of primitive man that are discovered from time to time 
