In its generic signification, it is applicable to every kind of action, whether of matter or of mind whether intelligent or unintelligent whether free or necessary action. Physical law is a term that represents the order of sequence, in all the changes that occur under the law of necessity, whether in matter or mind. I mean all changes whether of state or action, that do not consist in the states or actions of free will.
Physical law is the law of the material universe.
It is also the law of mind, so far as its states and changes are involuntary. All mental states or actions, which are not free and sovereign actions of will, must occur under, and be subject to, physical law. They cannot possibly be accounted for, except as they are ascribed to the law of necessity or force. Moral law is a rule of moral action with sanctions. It is that rule to which moral agents ought to conform all their voluntary actions, and is enforced by sanctions equal to the value of the precept.