The question, which has been attended with so long and obstinate debates, concerning the metaphysical doctrines of liberty and necessity, and the ******* of human actions, is not even yet finally and satisfactorily settled.
The negative is made out by an argument which seems to amount to demonstration, that every event requires a cause, a cause why it is as it is and not otherwise, that the human will is guided by motives, and is consequently always ruled by the strongest motive, and that we can never choose any thing, either without a motive of preference, or in the way of following the weaker, and deserting the stronger motive[26].
[26] Political Justice, Book IV, Chap. VII.
Why is it then that disbelief or doubt should still subsist in a question so fully decided?
For the same reason that compels us to reject many other demonstrations. The human mind is so constituted as to oblige us, if not theoretically, at least practically, to reject demonstration, and adhere to our senses.
The case is thus in the great question of the non-existence of an external world, or of matter. How ever much the understanding may be satisfied of the truth of the proposition by the arguments of Berkeley and others, we no sooner go out into actual life, than we become convinced, in spite of our previous scepticism or unbelief, of the real existence of the table, the chair, and the objects around us, and of the permanence and reality of the persons, both body and mind, with whom we have intercourse. If we were not, we should soon become indifferent to their pleasure and pain, and in no long time reason ourselves into the opinion that the one was not more desirable than the other, and conduct ourselves accordingly.
But there is a great difference between the question of a material world, and the question of liberty and necessity. The most strenuous Berkleian can never say, that there is any contradiction or impossibility in the existence of matter. All that he can consistently and soberly maintain is, that, if the material world exists, we can never perceive it, and that our sensations, and trains of impressions and thinking go on wholly independent of that existence.
But the question of the ******* of human actions is totally of another class. To say that in our choice we reject the stronger motive, and that we choose a thing merely because we choose it, is sheer nonsense and absurdity; and whoever with a sound understanding will fix his mind upon the state of the question will perceive its impossibility.
In the mean time it is not less true, that every man, the necessarian as well as his opponent, acts on the assumption of human liberty, and can never for a moment, when he enters into the scenes of real life, divest himself of this persuasion.
Let us take separately into our consideration the laws of matter and of mind. We acknowledge generally in both an established order of antecedents and consequents, or of causes and effects.
This is the sole foundation of human prudence and of all morality. It is because we foresee that certain effects will follow from a certain mode of conduct, that we act in one way rather than another. It is because we foresee that, if the soil is prepared in a certain way, and if seed is properly scattered and covered up in the soil thus prepared, a crop will follow, that we engage in the labours of agriculture. In the same manner, it is because we foresee that, if lessons are properly given, and a young person has them clearly explained to him, certain benefits will result, and because we are apprised of the operation of persuasion, admonition, remonstrance, menace, punishment and reward, that we engage in the labours of education. All the studies of the natural philosopher and the chemist, all our journeys by land and our voyages by sea, and all the systems and science of government, are built upon this principle, that from a certain method of proceeding, regulated by the precepts of wisdom and experience, certain effects may be expected to follow.
Yet, at the same time that we admit of a regular series of cause and effect in the operations both of matter and mind, we never fail, in our reflections upon each, to ascribe to them an essential difference. In the laws by which a falling body descends to the earth, and by which the planets are retained in their orbits, in a word, in all that relates to inanimate nature, we readily assent to the existence of absolute laws, so that, when we have once ascertained the fundamental principles of astronomy and physics, we rely with perfect assurance upon the invariable operation of these laws, yesterday, to-day, and for ever. As long as the system of things, of which we are spectators, and in which we act our several parts, shall remain, so long have the general phenomena of nature gone on unchanged for more years of past ages than we can define, and will in all probability continue to operate for as many ages to come. We admit of no variation, but firmly believe that, if we were perfectly acquainted with all the causes, we could, without danger of error, predict all the effects. We are satisfied that, since first the machine of the universe was set going, every thing in inanimate nature has taken place in a regular course, and nothing has happened and can happen, otherwise than as it actually has been and will be.
