Let us first consider the scientific aspects of the doctrine of second
causes, and the doctrine of God's immediate acting in various
departments (or all departments) of nature.

1. We cannot deny that the will of man is a real cause, producing
continual changes in the world about us. More than this, if there are
not also second causes outside of the will of free intelligent
personalities, the whole universe must be a gigantic deception; for it
seems to be full of second causes. Long chains of what seem like second
causes exist, made up of infinite numbers of links, as when the sun
carries an amount of water up into the air, the latter dropping the
water upon a mountain in the form of rain, gravity rolling it down the
slope in vast force, sweeping away villages and towns, changing the
fates of individuals and of nations. To quote two familiar examples from
Stewart and Tait: "In a steam engine the amount of work produced depends
upon the amount of heat carried from the boiler into the condenser; and
this amount depends in its turn upon the amount of coal which is burned
in the furnace of the engine. In like manner the velocity of the bullet
which issues from the rifle depends upon the transformation of the
energy of the powder; this in turn depends upon the explosion of the
percussion cap; this again upon the fall of the trigger; and lastly this
upon the finger of the man who fires the rifle."[54] Thus even the very
strongest opponents of the idea of second causes never deny that the
latter seem to surround us on every side, and that it would be possible
to trace a continuous line of apparent effects and causes back to the
very beginning.

[Footnote 54: "The Unseen Universe," p. 184.]

This view of the matter, it is evident, readily leads to a deistic view