The legislators who framed the ancient republics knew that their business was too arduous to be accomplished with no better apparatus than the metaphysics of an undergraduate and the mathematics and arithmetic of an exciseman.  They had to do with men, and they were obliged to study human nature.  They had to do with citizens, and they were obliged to study the effects of those habits which are communicated by the circumstances of civil life.  They were sensible that the operation of this second nature on the first produced a new combination,—­and thence arose many diversities amongst men, according to their birth, their education, their professions, the periods of their lives, their residence in towns or in the country, their several ways of acquiring and of fixing property, and according to the quality of the property itself, all which rendered them, as it were, so many different species of animals.  From hence they thought themselves obliged to dispose their citizens into such classes, and to place them in such situations in the state, as their peculiar habits might qualify them to fill, and to allot to them such appropriated privileges as might secure to them what their specific occasions required, and which might furnish to each description such force as might protect it in the conflict caused by the diversity of interests that must exist, and must contend, in all complex society:  for the legislator would have been ashamed that the coarse husbandman should well know how to assort and to use his sheep, horses, and oxen, and should have enough of common sense not to abstract and equalize them all into animals, without providing for each kind an appropriate food, care, and employment,—­whilst he, the economist, disposer, and shepherd of his own kindred, subliming himself into an airy metaphysician, was resolved to know nothing of his flocks but as men in general.  It is for this reason that Montesquieu observed, very justly, that, in their classification of the citizens, the great legislators of antiquity made the greatest display of their powers, and even soared above themselves.  It is here that your modern legislators have gone deep into the negative series, and sunk even below their own nothing.  As the first sort of legislators attended to the different kinds of citizens, and combined them into one commonwealth, the others, the metaphysical and alchemistical legislators, have taken the directly contrary course.  They have attempted to confound all sorts of citizens, as well as they could, into one homogeneous mass; and then they divided this their amalgama into a number of incoherent republics.  They reduce men to loose counters, merely for the sake of simple telling, and not to figures, whose power is to arise from their place in the table.  The elements of their own metaphysics might have taught them better lessons.  The troll of their categorical table might have informed them that there was something else in the intellectual world besides substance and quantity.  They might learn from the catechism of metaphysics that there were eight heads more,[123] in every complex deliberation, which they have never thought of; though these, of all the ten, are the subject on which the skill of man can operate anything at all.