hich 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.

These metaphysic rights entering into common life, like rays of light
which pierce into a dense medium, are, by the laws of Nature, refracted
from their straight line. Indeed, in the gross and complicated mass of
human passions and concerns, the primitive rights of men undergo such a
variety of refractions and reflections that it becomes absurd to talk of
them as if they continued in the simplicity of their original direction.