The moment you abate anything from the full rights of men each to govern himself, and suffer any artificial, positive limitation upon those rights, from that moment the whole organization of government becomes a consideration of convenience. This it is which makes the constitution of a state, and the due distribution of its powers, a matter of the most delicate and complicated skill. It requires a deep knowledge of human nature and human necessities, and of the things which facilitate or obstruct the various ends which are to be pursued by the mechanism of civil institutions. The state is to have recruits to its strength and remedies to its distempers. What is the use of discussing a man's abstract right to food or medicine? The question is upon the method of procuring and administering them. In that deliberation I shall always advise to call in the aid of the farmer and the physician, rather than the professor of metaphysics. The science of constructing a commonwealth, or renovating it, or reforming it, is, like every other experimental science, not to be taught _a priori_. Nor is it a short experience that can instruct us in that practical science; because the real effects of moral causes are not always immediate, but that which in the first instance is prejudicial may be excellent in its remoter operation, and its excellence may arise even from the ill effects it produces in the beginning. The reverse also happens; and very plausible schemes, with very pleasing commencements, have often shameful and lamentable conclusions. In states there are often some obscure and almost latent causes, things which appear at first view of little moment, on which a very great part of its prosperity or adversity may most essentially depend. The science of government being, therefore, so practical in itself, and intended for such practical purposes, a matter which requires experience, and even more experience than any person can gain in his whole life, however sagacious and observing he may be, it is with infinite caution that any man ought to venture upon pulling down an edifice which has answered in any tolerable degree for ages the common purposes of society, or on building it up again without having models and patterns of approved utility before his eyes.