Propositions, which pass under this name, are in fact of various kinds; some are universal, or without exceptions; some have few exceptions; some have many. This difference amongst them however does not depend on the objects to which they refer being human emotions or human actions. There is the same variety in those general laws which regard mere physical phenomena. It is, for example, a general law, that the heavenly bodies gravitate to each other with forces that are directly as the masses of the bodies, and inversely as the squares of their distances. This is a law to which there is no exception. Again, it is a general law that bodies are expanded by the addition of heat: but to this law there are exceptions. That peculiar compound of oxygen and hydrogen, which at the ordinary temperature of our climate is called water, in some circumstances expands and in others contracts on the addition of heat. It is evident, however, that the exception here stated does not render the general law useless. It is still highly serviceable to know that the great majority of substances are susceptible of expansion by an increase of temperature, and serviceable also to know that there are some which contract. But perhaps the subject may be the most forcibly illustrated by

referring to the general laws respecting the operation of medicines on the human body. The treatises of medical writers are in a great degree necessarily made up of general rules, asserting the efficacy of certain agents in curing certain disorders, or in occasioning certain states of the body. The mere medical classification of substances, is in fact laying down general rules respecting their action. When they are marshalled under the names of narcotics, cathartics, diaphoretics, an assertion is made that they produce the effects indicated by their names, on the generality of human bodies. In other words, certain general laws are laid down regarding the operation of these medicincs on the human frame, although these laws are not laws without exceptions: opium, the great narcotic, when applied to some peculiar constitutions, produces restlessness instead of repose.

The reason of the want of universality of these laws is easy to explain. Human bodies are physical compounds, having a general resemblance to each other in form, materials, and composition; but differing from each other more or less in all these circumstances, and even varying in themselves at different times. Being thus dissimilar and variable compounds, it would

be a violation of the uniform operation of causes and effects, if they were all affected alike, and affected in a similar way at all times by the application of the same substance; and yet being compounds resembling each other in a greater degree than they differ, and varying in themselves only to a comparatively small extent, it would be equally a violation of that uniformity, if in the majority of instances they were not affected alike and in a uniform manner. So far as they resemble they will be similarly influenced so far as they differ they will be differently influenced.

In the same way that the bodies of men are dissimilar and variable physical compounds, the minds of men are dissimilar and variable moral compounds; and the same circumstances operate differently on one mind from what they do on another, because the two minds are different in their constitution. The agents are the same, but the substances acted upon being in some respects unlike, different results must necessarily ensue. But as minds resemble each other in a great many points, however they may differ in others, there will be a similarity in the effects produced on most of them by the same causes; and just as certain general rules may be laid down in regard to the action of medicine on the human constitu

tion, other general rules may be laid down in respect to the influence of circumstances on human conduct.

In both cases, general laws may vary in their character. Some may have no exceptions, others may have numerous ones; but this will not derogate from the utility of knowing these laws, and knowing the degree of their generality, nor from the power of applying them to particular occasions. It would detract little from the virtue of arsenic, or any other medicine, in the treatment of ague, if it failed in curing the disease in one case out of a hundred, and nothing from the wisdom of employing it as a remedy. The same remark holds equally true of laws regarding moral conduct. The utility of checking the accounts of public servants would be little diminished by the circumstance, that it did not invariably succeed in keeping them honest.

""Tis certain," says Hume, "that general principles, however intricate they may seem, "must always, if they are just and sound, pre"vail in the general course of things, though they "may fail in particular cases; and it is the chief "business of philosophers to regard the general "course of things. I may add, that it is also the "chief business of politicians, especially in the

"domestic government of the state, when the "public good, which is or ought to be their ob

ject, depends on the concurrence of a multitude "of causes, not as in foreign politics, upon acci"dents and chances, and the caprices of a few * " persons

If these considerations are valid, there is no obstacle to deducing the theory of government from the nature of man, on account of any inability on our part to lay down general rules; for this is an operation which we are continually performing, and on such rules we are continually acting. Nor yet is there any obstacle in the circumstance of such rules not being universal; for whether they are universal or attended with exceptions, it is alike useful to apply them: we can equally deduce from them the needful practical conclusions.

If, turning from these particular objections, we try to reach the essence of the doctrine, that it is impossible to build a theory of government on general principles, it appears to be this:

"We cannot deduce the effects of political arrangements from the general principles of human nature, but must have seen those very

* Essay on Commerce.