◊ 274. Reasoning implies the existence of antecedent or assumed propositions.

In attempting to give some explanation of the reasong power, it is to be remarked further, that reasoning, oth in its inception and its prosecution, has this charcteristic, that it necessarily proceeds, in a great degree, pon assumptions. As every deductive process implies a comparison of propositions, there must, of course, be some propositions given, by the aid of which the comparison is prosecuted. There must be something assumed as known, by means of which to find out what is unknown. Accordingly, assumed propositions (either those which are known to be true, or, for the purposes of argument, are regarded as such) are always found at the commencement of the series; and they are also introduced frequently in its progress, particularly in Moral reasoning. But the propositions which are assumed are not always expressed; especially those which, from the circumstance of their being representative of elementary convictions of the understanding, are denominated PRIMARY TRUTHS. (See chap. i. of the Introduction.)" In every process of reasoning," says Abercrombie, "we proceed by founding one step upon another which has gone before it; and when we trace such a process backward, we must arrive zat certain truths which are recognised as fundamental, requiring no proof and admitting of none."

But when we say that reasoning proceeds upon assumptions, it does not necessarily follow that it proceeds upon propositions which are unknown or doubtful. The propositions which are referred to are assumed in reference to the reasoning power, and not in reference to other sources of knowledge, which the understanding possesses besides reasoning. Whatever things are known by Original Suggestion, whatever are known by Consciousness, or by the direct communication of the Senses, or by undoubted Memory or Testimony, as they cannot be made clearer by reasoning, but fully command our belief of themselves, are at once adopted by reasoning into its own processes, and employed as helps in eliciting the remote and unperceived truths which it is in search of But, as has been intimated, this adoption is not always a

formal and acknowledged one, but often silently, and by implication. No one would think of formally and repeatedly enunciating, as he advances in an argument, the truth of his own existence or of his personal identity; and not much more would he think of enunciating that every effect has its cause, or that nature is uniform in her operations, or that a combination of means conspiring to a particular end indicates intelligence; truths which are so essential and familiar to the human intellect, that we daily base the most important conclusions upon them, while at the same time we scarcely think of their exist

ence.

275. Of reasoning A PRIORI.

There are various methods of conducting ratiocination. One method of reasoning, for instance, is termed A PRIORI. A PRIORI reasoning is that whereby an effect is proved from a cause, whether that cause be directly proximate or be remote. For instance, a nation is possessed of a well-ordered government and wise rulers. And we infer, A PRIORI, that justice will be carefully administered, and that there will be a high degree of harmony, security, and prosperity among the people.

Under the results of this form of reasoning may be embraced also any conclusion which is ascertained and proved by something previously existing, whether such antecedent be a cause in the proper sense of the term, or possess merely an accidental priority. It embraces also those cases where, in view of the correspondence and adaptation of things which we so generally witness in the universe, we are impelled, by the consideration of the nature of one thing, to believe in the existence of something else corresponding to it.-One of the various arguments which has a bearing on the existence of God is of this description. It is to this effect. We are so constituted that we naturally and necessarily form certain ideas, such as the ideas of space, time, and infinity; and by the aid of these we frame the additional ideas of unlimited space and unlimited time, or IMMENSITY and ETERNITY. These conceptions are Absolute or Unconditioned; in other words, we cannot possibly conceive of the oppo

site; we cannot conceive of a state of things where time and space are not; so that, in view of the human intellect, there are, and necessarily must be, both an eternity of duration and illimitability of space; which, however, we commonly express by the single terms ETERNITY and IMMENSITY. Nor are we at liberty to suppose that the human intellect is deceived as to the results involved in the formation of these conceptions; in other words, we are not at liberty to suppose that it is led by its very constitution to form conceptions of what does not exist, and to which there is nothing corresponding. So that we may regard ourselves as fully and legitimately possessed of the fact or reality of eternity, and also of immensity or boundless It is obvious that in this way we posspace. sess the knowledge of a state of things which is adapted, and adapted exclusively, to the nature of God. We naturally inquire, why should there be ETERNITY without an Eternal Being of whom eternity is predicable? Why should there be immensity of space without an Omnipresent Being who may occupy it? If there be no God, but nothing but limited finite beings, then there is, comparatively speaking, an infinity of time and of space, which is unoccupied and unavailable. But, as this is inconsistent with that harmony and adaptation of things which we witness in every other case, we are led to infer, A PRIORI, that there is, and must be, a God.

A PRIORI reasoning is more frequently made use of, than anywhere else, in the mathematics, and in all cases of demonstration. The definitions which are given embrace general truths, from which other truths are evolved or brought out by a successive comparison of propositions. We say, for instance, that a square is a figure, which has all its sides equal, and all its angles right angles. In this definition there is not only involved equality of sides, but equality of angles. And it is evident, that if the definition were altered, and were so restricted as to exclude the notion of equality of angles, many properties which are now demonstrated of the square would be unsusceptible of proof. In other words (and it is the same of other analogous cases), such properties are deVOL. I.—G G

duced by an A PRIORI process from the general notions - involved in the definition of a square.

◊ 276. Of reasoning A POSTERIORI.

Another method of reasoning is termed A POSTERIORI. A POSTERIORI reasoning is that by which either a cause is proved from an effect; or, in more general terms, by which a conclusion is proved by something posterior in time, whether it be properly an effect or not. For instance (reversing one of the illustrations in the last section), if justice is not properly administered among the people, and if discord and insecurity prevail, we infer, A POSTERIORI, that there is a deficiency in the constitution of the country, or in the rulers, or in both.-It is narrated of Aristippus the Cyreniac, that he was once shipwrecked on an unknown coast. As he was there wandering about on the desert shore, he discovered some geometrical diagrams traced in the sand. He immediately called out to his companions to be of good courage, as he saw the traces and evidences of human beings. In other words, reasoning A POSTERIORI, or from effects to causes, and combining with that process the general principle that a combination of means conspiring to a particular end indicates design, he did not hesitate to infer, from what he had discovered, that the country either was or had been inhabited.

The A PRIORI process, as we have already had occasion to see, is sometimes employed in proving the existence of God; but still more frequently, and probably to better effect, the method of reasoning A POSTERIORI. The idea of God is not simple, but complex; embracing, in particular, the two great elements of intelligence and power. Accordingly, in endeavouring to prove his existence from the works of nature, we assume, on the ground of their being original and necessary suggestions of the human intellect, the following propositions: (1.) That there is no beginning or change of existence without a cause; and, (2.) That means conspiring to a particular end indicate design or intelligence. With these two propositions given, we look at the multiplied works of nature, we contemplate them in their progress, harmony, and results ;

and thus, reasoning A POSTERIORI, from the consequent to the antecedent, from the effect to the cause, we infer the existence of God.

§ 277. Of reasoning A FORTIORI.

Another process of ratiocination is denominated rea→ soning A FORTIORI. This consists in deducing a proposi tion as true from another known or admitted proposition, the truth of which is less obvious or less probable. Hence the application of the term A FORTIORI, which indicates that the conclusion is clearer or stronger. Thus, if a man who merely robs on the highway is worthy of death, then, A FORTIORI, the murderer is deserving of the same punishment. Again, if he who murders his enemy is worthy of death, still more is he who commits parricide. We have an instance of this species of reasoning in the passage of the Apostle Paul, where he shows that the Almighty will not fail to bestow upon good men the necessaries of life. "He that spared not his own Son, how shall he not with him freely give us all things." If he gave us the greater blessing of his Son, A FORTIORI he will give us such other inferior things as may be necessary for us.

278. Of differences in the power of reasoning.

The faculty of reasoning exists in different individuals in very different degrees. There is the same diversity here which is found to exist in respect to every other mental susceptibility and mental process. In some persons it is not even powerful enough to meet the ordinary exigences of life, and hardly rescues its possessor from the imputation of idiocy; in others it elevates human nature, and bestows extraordinary grasp and penetration. And between the extremes of extraordinary expansion and marked imbecility, there are multitudes of distinct grades, almost every possible variety.

This difference depends on various causes.-(1.) It will depend, in the first place, on the amount of knowledge which the reasoner possesses. No man can permanently sustain the reputation of great ability in argument without having previously secured a large fund of knowl