Action is either necessary or free. The great multitude of creatures
are wholly necessary agents. Even in free agents, most of what is in
them, and much that proceeds from them, is of necessity, and beyond
the control of their will. Of necessary action, whether material or
mental, we shall have nothing further to say. It is governed by the
Eternal Law, but it is not matter of moral philosophy. Henceforth we
have to do with that law, only as it is received in free agents, as
such, to be the rule of their conduct. The agents being free, the law
must be received in a manner consonant with their freedom. It is
proper to a free and rational being to guide itself, not to be dragged
or pushed, but to go its own way, yet not arbitrarily, but according
to law. The law for such a creature must be, not a physical
determinant of its action, but a law operating in the manner of a
motive to the will, obliging and binding, yet not constraining it: a
law written in the intellect after the manner of knowledge: a law
within the mind and consciousness of the creature, whereby it shall
measure and regulate its own behaviour. This is the _natural law of
conscience_. It is the Eternal Law, as made known to the rational
creature, whereby to measure its own free acts. The Eternal Law is in
the Mind of God: the Natural Law in the minds of men and angels. The
Eternal Law adjusts all the operations of creatures: the Natural Law,
only the free acts of intellectual creatures. And yet, for binding
force, the Natural Law is one with the Eternal Law. On a summer
evening one observes the sunset on the west coast; the heavens are all
aglow with the sun shining there, and the waters are aglow too,
reflecting the sun's rays. The Eternal Law is as the sun there in the
heavens, the Natural Law is like the reflection in the sea. But it is
one light.

2. It is called the _Natural Law_, first, because it is found, more or