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.