"Let it be observed also, that usually we make little or no distinction in common language, between a subject that is physically or mathematically universal." You will find that some political economists lay down general propositions, and reason from them as though they possessed a mathematical universality. But, from the nature of the science, this cannot be the case. It is a moral science, and its general propositions have only a moral universality. I mean that these rules have a good many exceptions. For example; one of its principles is, that the Government should not interfere with matters of trade-a very good rule, as a general rule; but when we are told that this rule is so inflexible that the Government must not interfere even in behalf of humanity and religion, then we contend that its advocates claim for this rule a universality to which it is not entitled. In this sense we deny the soundness of the rule. Nay, even those political economists who maintain most strongly this principle, maintain at the same time that the Government ought to pass laws for the regulation of the currency -a subject with which trade has a very close affinity. It is rarely that a mathematical universality can be obtained with regard to those propositions that we usually act upon in ordinary life. We believe that all noblemen have honourable and patriotic feelings-that all judges are impartial in their decisions-that all London merchants are honest in their dealings-that no clergyman would tell an untruth-that our friends, whose constancy we have tried, will never desert us-that a man who has maintained a high reputation for thirty years will maintain it as long as he lives. But we have only moral evidence for all these propositions, and we can get no more. He who, in these and similar instances, would refuse to act until he should obtain mathematical evidence, would show a want of that wisdom and decision which are essential to the good administration of the affairs either of a family, a commercial establishment, or a political community. 13. We may observe, that all arguments formed on the relation of subject and attribute may also be brought under the relation of genus and species. All subjects may be distributed into classes, according to their attributes. Thus, some horses are of a grey colour, Now, we may consider grey as an attribute of the horses, or we may consider grey horses as forming a class, and our reasonings will be substantially the same, though, perhaps, changed in regard to form. Let us take an example from Dr. Watts: 66 No liar is fit to be believed. Every good christian is fit to be believed. Here the words "fit to be believed" express an attribute, and, as this attribute will not apply to both the subjects, we infer that these subjects are different. See page 40. But let us suppose that these words "fit to be believed" denote a class, then the argument will stand thus :— "No man who is fit to be believed is a liar. Every good christian is fit to be believed. Therefore, no good christian is a liar.” 66 Here "fit to be believed" denotes a class of a good christian" is one of that class. Let us take another instance of a different kind : "Whosoever loves God shall be saved. All the lovers of God have their imperfections. Therefore, some who have imperfections shall be saved." Here we consider "shall be saved" and "have their imperfections," as denoting attributes, and as these attributes belong to the same subject, we infer they are not incompatible with each other. See page 39. But we may put the argument in a different form; we may consider the words, "lovers of God," as denoting a class or genus, and "some who have imperfections," as a species under that class. The reasoning would then stand thus :— "All the lovers of God shall be saved. Some who have imperfections are lovers of God. Therefore, some who have imperfections shall be saved." 14. So, arguments founded on the principle of cause and effect may be brought under the principle of genus and species. One of the examples taken from Dr. Watts will exemplify this. "Some afflictions are good for us, because they further our salvation." Here we have evidently cause and effect, and this, in fact, is the best mode of stating the argument. But in the syllogism, Dr. Watts makes a class of "all those things that further our salvation," and then "some afflictions" become a subordinate class under that larger class, a species under a genus. Whatsoever furthers our salvation is good for us. Again, "A good education is highly valuable, for it softens the manners, and ameliorates the dispositions of the heart." Here is the relation of cause and effect. But a scholastic logician would not be satisfied with the argument in this form, but would turn it into genus and species. This is done by making the effect a genus, and the cause a species, thus :— 66 Everything that softens the manners, and ameliorates the disposition of the heart, is highly valuable. But a good education softens the manners, and ameliorates the dispositions of the heart. Therefore, a good education is highly valuable." An You will observe, that this relation of genus and species does not strengthen your argument. It rather weakens it; or, at least, it widens the field of objection. opponent might deny your first proposition. He might say, "I do not admit that everything that softens the manners and ameliorates the disposition of the heart is highly valuable: For there are some things that produce these effects, but at the same time produce other effects of a dangerous character. Such things, for instance, it might be said, are theatrical exhibitions." Here you see a new field of argumentation is at once thrown open. Had you stuck to your original principle of cause and effect, you would have been on safer ground. It is never advisable in argumentation to put yourself in a position to be called upon to prove the affirmative of a universal proposition. If a single exception can be adduced, your proposition is refuted, and your argument is overthrown. It is generally best to argue from those principles of reasoning which arise from the relation of the things themselves, and not to attempt by mere verbal changes to bring your reasonings under a different principle. You should be on your guard against this practice, lest you fall into that system of scholastic logic which refers only to the use of words, and leaves unnoticed the nature of things. SECTION IV. THE RELATION OF CAUSE AND EFFECT-PHYSICAL CAUSES. THE Relation of Cause and Effect is a principle of extensive use in the art of reasoning. But as causes are of various kinds, we must consider them separately in different sections; and in this section we shall confine our attention to those causes that refer to material substances, and are consequently styled physical. We shall, in the subsequent sections, consider those causes that are moral, conditional, and final. We may observe, with regard to these four kinds of causes-physical, moral, conditional, and final-the first has reference to the physical sciences, as botany, physiology, geography, chemistry, &c.; the second has a reference to the sciences of politics and political economy; the third has a reference to jurisprudence and the affairs of ordinary life; the fourth has a reference to ethics and theology. We do not mean an exclusive reference, but a general reference. To 1. The first class of causes we call physical causes. this class of causes we refer all those effects which are produced by the uniform and necessary operations of nature. Thus, it is an established law of nature that the earth should move round the sun, and that the moon should move round the earth. All the phenomena which result from the revolutions of the heavenly bodies are the result of natural causes. It is a law of nature that all bodies on the earth should tend towards the centre; and that different kinds of matter, whether fluid or solid, should have certain properties, and that some of them should have an affinity for each other. Hence, all reasonings connected with astronomy, mechanics, chemistry, and the other branches of experimental philosophy, are founded on natural causes. The reasonings founded on this class of causes amount to demonstration. The cause necessarily and invariably produces the effect. The following are examples : "He sendeth the springs into the valleys, which run among the hills. They give drink to every beast of the field: the wild asses quench their thirst. By them the fowls of the heaven have their habitation, which sing among the branches. He watereth the hills from his chambers. He causeth the grass to grow for the cattle, and herb for the service of man: that he may bring forth food out of the earth; and wine that maketh glad the heart of man, and oil to make his face to shine, and bread which strengtheneth man's heart."-Psalm civ. 10-15. "The benefits arising from the winds are almost innumerable; they purify the air, moderate the heat, dry wet lands and damp houses, chase away the fogs and hazy weather, and bring us rain in due season; also frost and snow, and even mild weather. They are particularly serviceable for navigation and commerce. When the air is so full of heavy vapours that it can no longer sustain them, then these small moist particles run together, and fall down in fine drops, which we call rain. The rain descending in drops is a further manifestation of Divine wisdom; for if it fell in strong streams it would injure the earth, by washing away its fine light mould from the roots and seeds of plants; and we should suffer great inconvenience from it."- Joyce's Catechism of Nature. "The annual overflowing of the Nile is caused by the periodical rains in Ethiopia. The river begins to rise in the latter end of June, and attains its utmost height about the middle of August, when Egypt presents the appearance of a vast sea, while the cities and towns appear like so many islands; after this the waters gradually subside, and about the end of November the river has returned to its ordinary limits. During this period the earth, or mud, which the waters held in solution, has fallen on the soil; and on the retiring of the waters, the whole land is covered with a rich manure; and, according to Herodotus, required so little cultivation, that, in some cases, it was only necessary that the seed should be thrown upon the surface, and trodden down by pigs."-Lectures on Ancient Commerce. 2. There are four ways of reasoning in regard to these physical causes. First, from the existence of the cause, we may infer the existence of the effect; if the sun has arisen, |