Thus we have engaged in the discussion of various topics respecting the mode in which improvement may most successfully be introduced into the institutions of society. We have seen, under the heads of resistance, revolution, associations and tyrannicide, that nothing is more to be deprecated than violence and a headlong zeal, that everything may be trusted to the tranquil and wholesome progress of knowledge, and that the office of the enlightened friend of political justice, for the most part, consists in this only, a vigilant and perpetual endeavour to assist the progress. We have traced the effects which are to be produced by the cultivation of truth and the practice of sincerity. It remains to turn our attention to the other branch of the subject proposed to be investigated in the present book; the mode in which, from the structure of the human mind, opinion is found to operate in modifying the conduct of individuals.
Some progress was made in the examination of this point in an earlier division of the present work. An attentive enquirer will readily perceive that no investigation can be more material, to such as would engage in a careful development of the principles of political justice. It cannot therefore be unproductive of benefit that we should here trace into their remoter ramifications the principles which were then delivered; as well as turn our attention to certain other considerations connected with the same topic which we have not hitherto had occasion to discuss. Of the many controversies which have been excited relative to the operation of opinion, none are of more importance than the question respecting free will and necessity, and the question respecting self-love and benevolence. These will occupy a principal portion of the enquiry.
We will first endeavour to establish the proposition that all the actions of men are necessary. It was impossible that this principle should not, in an indirect manner, be frequently anticipated in the preceding parts of this work. But it will be found strongly entitled to a separate consideration.
The doctrine of moral necessity includes in it consequences of the highest moment, and leads to a more bold and comprehensive view of man in society than can possibly be entertained by him who has embraced the opposite opinion.
To the right understanding of any arguments that may be adduced under this head, it is requisite that we should have a clear idea of the meaning of the term necessity. He who affirms that all actions are necessary means that the man who is acquainted with all the circumstances under which a living or intelligent being is placed upon any given occasion is qualified to predict the conduct he will hold, with as much certainty as he can predict any of the phenomena of inanimate nature. Upon this question the advocate of liberty in the philosophical sense must join issue. He must, if he mean anything, deny this certainty of conjunction between moral antecedents and consequents. Where all is constant and invariable, and the events that arise uniformly correspond to the circumstances in which they originate, there can be no liberty.
It is generally acknowledged that, in the events of the material universe, everything is subjected to this necessity. The tendency of investigation and enquiry, relatively to this topic of human science, has been more effectually to exclude the appearance of irregularity, as our improvements extended.
Let us recollect what is the species of evidence that has satisfied philosophers upon this point. Their only solid ground of reasoning has been from experience.
The argument which has induced mankind to conceive of the universe as governed by certain laws has been an observed similarity in the succession of events.
If, when we had once remarked two events succeeding each other, we had never had occasion to see that individual succession repeated; if we saw innumerable events in perpetual progression, without any apparent order, so that all our observation would not enable us, when we beheld one, to pronounce that another, of such a particular class, might be expected to follow; we should never have formed the conception of necessity, or have had an idea corresponding to that of laws and system.
Hence it follows that all that, strictly speaking, we know of the material universe is this uniformity of events. When we see the sun constantly rise in the morning, and set at night, and have had occasion to observe this phenomenon invariably taking place through the whole period of our existence, we cannot avoid receiving this as a law of the universe, and a ground for future expectation. But we never see any principle or virtue by which one event is conjoined to, or made the antecedent of, another.
Let us take some familiar illustrations of this truth. Can it be imagined that any man, by the inspection and analysis of gunpowder, would have been enabled, previously to experience, to predict its explosion? Would he, previously to experience, have been enabled to predict that one piece of marble, having a flat and polished surface, might with facility be protruded along another in a horizontal, but would, with considerable pertinacity, resist separation in a perpendicular direction? The simplest phenomena, of the most hourly occurrence, were originally placed at an equal distance from human sagacity.
There is a certain degree of obscurity, incident to this subject, arising from the following circumstance. All human knowledge is the result of perception.
We know nothing of any substance, a supposed material body, for example, but by experience. If it were unconjoined, and bore no relation, to the phenomena of any other substance, it would be no subject of human intelligence.