And, as towards our fellow-creatures, so in relation to ourselves, our moral sentiments are all involved with, and take their rise in, the delusive sense of liberty. It is in this that is contained the peculiar force of the terms virtue, duty, guilt and desert. We never pronounce these words without thinking of the action to which they refer, as that which might or might not be done, and therefore unequivocally approve or disapprove in ourselves and others. A virtuous man, as the term is understood by all, as soon as we are led to observe upon those qualities, and the exhibition of those qualities in actual life, which constitute our nature, is a man who, being in full possession of the freedom of human action, is engaged in doing those things which a sound judgment of the tendencies of what we do pronounces to be good.
Duty is a term that can scarcely be said to have a meaning, except that which it derives from the delusive sense of liberty. According to the creed of the necessarian, it expresses that mode of action on the part of the individual, which constitutes the best possible application of his capacity to the general benefit(30). In the mean time, if we confine ourselves to this definition, it may as well be taken to describe the best application of a knife, or any other implement proceeding from the hands of the manufacturer, as of the powers of a human being.
But we surely have a very different idea in our minds, when we employ the term duty. It is not agreeable to the use of language that we should use this term, except we speak of a being in the exercise of volition.
(30) Political Justice, Book II, Chap. IV.
Duty then means that which may justly be required of a human creature in the possession of liberty of action. It includes in its proper sense the conception of the empire of will, the notion that mind is an arbiter, that it sits on its throne, and decides, as an absolute prince, this way or that.
Duty is the performance of what is due, the discharge of a debt (debitum). But a knife owes nothing, and can in no sense be said to be held to one sort of application rather than another; the debt can only belong to a human being in possession of his liberty, by whom the knife may be applied laudably or otherwise.
A multitude of terms instantly occur to us, the application of which is limited in the same manner as the term duty is limited: such are, to owe, obligation, debt, bond, right, claim, sin, crime, guilt, merit and desert. Even reward and punishment, however they may be intelligible when used merely in the sense of motives employed, have in general acceptation a sense peculiarly derived from the supposed freedom of the human will.
The mode therefore in which the advocates of the doctrine of necessity have universally talked and written, is one of the most memorable examples of the hallucination of the human intellect. They have at all times recommended that we should translate the phrases in which we usually express ourselves on the hypothesis of liberty, into the phraseology of necessity, that we should talk no other language than that which is in correspondence with the severest philosophy, and that we should exert ourselves to expel all fallacious notions and delusions so much as from our recollection. They did not perceive what a wide devastation and destruction they were proposing of all the terms and phrases that are in use in the communications between man and man in actual life.—They might as well have recommended that we should rigorously bear in mind on the ordinary occasions of life, that there is no such thing as colour, that which we ordinary call by that name having no existence in external objects, but belonging only to our way of perceiving them.
The language which is suggested to us by the conception of the freedom of human actions, moulds the very first articulations of a child, "I will," and "I will not;" and is even distinctly conveyed by his gestures, before he arrives at the power of articulation. This is the explanation and key to his vehement and ungovernable movements, and his rebellion. The petulance of the stripling, the fervent and energetic exertions of the warrior, and the calm and unalterable resolution of the sage, all imply the same thing. Will, and a confidence in its efficiency, "travel through, nor quit us till we die." It is this which inspires us with invincible perseverance, and heroic energies, while without it we should be the most inert and soulless of blocks, the shadows of what history records and poetry immortalises, and not men.
Free will is an integral part of the science of man, and may be said to constitute its most important chapter. We might with as much propriety overlook the intelligence of the senses, that medium which acquaints us with an external world or what we call such, we might as well overlook the consideration of man's reason, his imagination or taste, as fail to dwell with earnest reflection and exposition upon that principle which lies at the foundation of our moral energies, fills us with a moral enthusiasm, prompts all our animated exertions on the theatre of the world, whether upon a wide or a narrow scale, and penetrates us with the most lively and fervent approbation or disapprobation of the acts of ourselves and others in which the forwarding or obstructing human happiness is involved.