To trace effects to their causes, is the object of all science; and by this object, as it is accomplished or incomplete, the progress of any particular science must be determined. The order of the moral is in reality as immutable as the laws of the physical world; and human actions are linked to their consequences by a necessity as inexorable as that which controls the growth of plants or the motion of the earth, though the connexion between cause and effect is not equally discernible. The depression of the nobles and the rise of the commons in England, after the statutes of alienation, were the result of causes as infallible in their operation as those which regulate the seasons and the tides. Repeated experiments have proved beyond dispute, that gold is heavier than iron. Is the superior value of gold to iron a fact more questionable? Yet is value a quality purely moral, and absolutely dependent on the will of man. The events of to-day are bound to those of yesterday, and those of to-morrow will be bound to those of to-day, no less certainly than the harvest of the present year springs from the grain which is the produce of former harvests. When by a severe and diligent analysis we have ascertained all the ingredients of any phenomenon, and have separated it from all that is foreign and adventitious, we know its true nature, and may deduce a general law from our experiment; for a general law is nothing more than an expression of the effect produced by the same cause operating under the same circumstances. In the reign of Louis XV., a Montmorency was convicted of an atrocious murder. He was punished by a short imprisonment in the Bastile. His servant and accomplice was, for the same offence at the same time, broken alive upon the wheel. Is the proposition, that the angles of a triangle are equal to two right angles, more certain than the ruin of a system under which such a state of things was tolerated? How, then, does it come to pass, that the same people who cling to one set of truths reject the other with obstinate incredulity? Cicero shall account for it:—"Sensus nostros non parens, non nutrix, non poeta, non scena depravat; animis omnes tendentur insidiæ." The discoveries of physical science, in the present day at least, allow little scope to prejudice and inclination. Whig and Tory, Radical and Conservative, agree, that fire will burn and water suffocate; nay, no tractarian, so far as we know, has ventured to call in question the truths established by Cuvier and La Place. But every proposition in moral or political science enlists a host of feelings in zealous support or implacable hostility; and the same system, according to the creed and prepossessions of the speaker, is put forward as self-evident, or stigmatized as chimerical. One set of people throw corn into the river and burn mills, in order to cheapen bread—another vote that sixteen shillings are equal to twenty-one, in order to support public credit—proceedings in no degree more reasonable than a denial that two and two make four, or using gunpowder instead of water to stop a conflagration. Again, in physical science, the chain which binds the cause to its effect is short, simple, and passes through no region of vapour and obscurity; in moral phenomena, it is long hidden and intertwined with the links of ten thousand other chains, which ramify and cross each other in a confusion which it requires no common patience and sagacity to unravel. Therefore it is that the lessons of history, dearly as they have been purchased, are forgotten and thrown away—therefore it is that nations sow in folly and reap in affliction—that thrones are shaken, and empires convulsed, and commerce fettered by vexatious restrictions, by those who live in one century, without enabling their descendants to become wiser or richer in the next. The death of Charles I. did not prevent the exile of James II., and, in spite of the disasters of Charles XII., Napoleon tempted fortune too often and too long. It is not, then, by the mere knowledge of separate facts that history can contribute to our improvement or our happiness; it would then exchange the character of philosophy treated by examples, for that of sophistry misleading by empiricism. The more systematic the view of human events which it enables us to gain, the more nearly does it approach its real office, and entitle itself to the splendid panegyric of the Roman statesman—"Historia, testis temporum, lux veritatis, vita memoriæ, magistra vitæ, nuntia vetustatis."
But while we insist upon the certainty of those truths which a calm examination of history confirms, and the sure operation of those general laws by which Providence in its wisdom has ordained that the affairs of this lower world shall be controlled—let it not be supposed that we for a moment doubt the truth which Demosthenes took such pains to inculcate upon his countrymen, that fortune in human affairs is for a time omnipotent. That fortune, which "erring men call chance," is the name which finite beings must apply to those secret and unknown causes which no human sagacity can penetrate or comprehend. What depends upon a few persons, observes Mr Hume, is to be ascribed to chance; what arises from a great number, may often be accounted for by known and determinate causes; and he illustrates this position by the instance of a loaded die, the bias of which, however it may for a short time escape detection, will certainly in a great number of instances become predominant. The issue of a battle may be decided by a sunbeam or a cloud of dust. Had an heir been born to Charles II. of Spain—had the youthful son of Monsieur De Bouillé not fallen asleep when Louis XVI. entered Varennes—had Napoleon, on his return from Egypt, been stopped by an English cruizer—how different would have been the face of Europe. The poco di piu and poco di meno has, in such contingencies, an unbounded influence. The trade-winds are steady enough to furnish grounds for the most accurate calculation; but will any man in our climate venture to predict from what quarter, on any particular day, the wind may chance to blow?
Therefore, in forming our judgment of human affairs, we must apply a "Lesbian rule," instead of one that is inflexible. Here it is that the line is drawn between science, and the wisdom which has for its object the administration of human affairs. The masters of science explore a multitude of phenomena to ascertain a single cause; the statesman and legislator, engaged in pursuits "hardliest reduced to axiom," examine a multitude of causes to explain a solitary phenomenon. The investigations, however, to which such questions lead, are singularly difficult, as they require an accurate analysis of the most complicated class of facts which can possibly engross our attention, and to the complete examination of which the faculties of any one man must be inadequate. The finest specimens of such enquiries which we possess are the works of Adam Smith and Montesquieu. The latter, indeed, may be called a great historian. He sought in every quarter for his account of those fundamental principles which are common to all governments, as well as of those peculiarities by which they are distinguished one from another. The analogy which reaches from the first dim gleam of civility to the last and consummate result of policy and intelligence, from the law of the Salian Franks to the Code Napoleon, it was reserved for him to discover and explain. He saw that, though the shape into which the expression of human thought and will was moulded as the family became a tribe, and the tribe a nation, might be fantastic and even monstrous—that the staple from which it unrolled itself must be the same. Treading in the steps of Vico, he more than realized his master's project, and in his immortal work (which, with all its faults, is a magnificent, and as yet unrivalled, trophy of his genius, and will serve as a landmark to future enquirers when its puny critics are not known enough to be despised) he has extracted from a chaos of casual observations, detached hints—from the principles concealed in the intricate system of Roman jurisprudence, or exposed in the rules which barely held together the barbarous tribes of Gaul and Germany—from the manners of the polished Athenian, and from the usages of the wandering Tartar—from the rudeness of savage