70 The Course of Nature. [January, 
everything that can he found to militate against it is put 
into the other. If the investigator is imbued with the true 
spirit of science, his search is equally vigorous for argu- 
ments to go into the two scales. When he says that the 
proposition is worthy of being received as true, he means, 
not that it bears any recognised seal of truth, but that the 
‘evidence in favour of it entirely preponderates over all that 
can be brought to bear against it. 
You will not understand me as maintaining that every 
individual man of science constantly maintains this spirit of 
impartiality any more than every Christian constantly lives 
up to the highest standard of his profession. Hot conflicts 
have sometimes raged, and there is no reason to suppose 
that they have entirely ceased, even now, in which each 
combatant could only see one scale. But the spirit I have 
described is that in which science exhorts her votaries to 
approach every question, and in which they will constantly 
endeavour to approach it if they are worthy of their pro- 
fession. 
Let us now approach our main theme, the course of 
visible nature. Let me again remind you that of the two 
universes, the seen and the unseen, I am only going to speak 
of the former. We find ourselves placed in this world in 
the midst of a vast theatre of activity. We see an atmo- 
sphere agitated by storms ; great masses of water rising in 
the air to form clouds, and, after falling to the earth, flowing 
as mighty rivers to the ocean ; countless forms of vegetation 
rising from the earth and then returning to it ; a sun sup- 
porting all life on our planet with its heat ; an infinitude of 
chemical changes going on around us ; countless stars 
moving through space with velocities which transcend all 
our conceptions. To all appearance these operations have 
been going on for millions of ages past, and may continue 
for millions of ages to come. As the thinking man contem- 
plates them he is led irresistibly to the conclusion that 
they do not go on at random, but that they are joined by 
connecting links, or are in some way the product of know- 
able causes. From his earliest infancy he sees connections 
between them which enable him to foresee results. He 
finds that fire burns, that the sun warms, that food satisfies 
his hunger, and that heavy bodies fall with a certainty 
which shows the forces at play to be invariable in their 
aCtion. To penetrate the mystery in which these forces are 
enshrouded, he has exerted the efforts of his intellect from 
its first dawn until the present time. What general con- 
clusions has he reached ? 
