diamond; the experiment was successful, and there was no longer any reasonable question as to the identity of the two substances.

The steps to be taken in the pursuit of knowledge for the purposes of argumentation can be, at this point, easily inferred, and are the following: When the investigator watches the curious phenomena of matter or of mind, his method is merely observational. When he goes into his laboratory and there tests and analyzes substances, or goes among men trying the effect of this or that motive, his method is purely experimental. If, after obtaining and verifying his facts, either by experiment or observation, he then infers a general conclusion concerning all other facts belonging to the same class, his method is inductive. When he adopts a given conclusion, the result of his own observation or experiment, or that of others, and applies it to this or that object or purpose, either to ascertain whether the object or purpose belongs to a given class, or to see what practical service may result therefrom, his method is deductive.

The student may illustrate these points by Newton's discovery and application of the law of gravitation; and by Franklin's electrical experiments and applications. For examples of inductive supplemented by deductive methods, see Acts v. 34-49; xi. 1-18; xv. 13-23. A pure deduction is found in Matt. xii. 25, 26.

2. Specific Classification. Under the two foregoing general types of reasoning are included certain

varieties which may be classified according to quality, rhetorical form, and logical method.

(1) Reasoning classified as to its quality.

a. Probable reasoning. It deals with facts included under observation, experiment, experience, and opinion. The quality is contingent and variable because the facts upon which it is based are variable.

From these remarks it is clear that probable reasoning is to be freely employed in the fields of theology, morality, politics, business, the arts, and in some of the sciences. Probable reasoning assumes much, and most men admit that it has this right. That there is mind, for instance, and that it is superior to matter, the reasoner assumes; and all feel that he has a right so to do. For assumption is not illogical where the evidence of the thing assumed is clearly within the range of ordinary understanding.

"We are also often obliged in probable reasoning to start from this or that admitted fact or truth (and these, perhaps not universally admitted), and proceed by merely probable inferences drawn from various, diverse, and often uncertain relations, till we reach the conclusion. Such reasons may be sufficient to incline the mind to a particular conclusion, as against those which tend to any other conclusion; but they are never quite sufficient to necessitate the conclusion and render any other impossible."

Pres. Champlin, Intellectual Philosophy.

Hence Lord Erskine claims that all proof outside of mathematics "is nothing but presumption of high order." Still, the conclusions reached may be sufficiently convincing to control human conduct.

Bishop Butler goes so far as to say that, "probability is the constant guide of human life."

"That

the evidence preponderates on one side is sufficient to determine the reason, and should be to determine the conduct. If it does not, it is evidence of something wrong in our character; and thus the fact that every question cannot be made demonstrably evident, becomes an important test and trial of character. Besides, as life has to do chiefly with things contingent, probable reasoning is much more used by us, and hence is much the most important to us." Examples of this kind of reasoning are the speeches of Cicero against Verres, of Burke in the impeachment of Warren Hastings, and of Webster in the trial of the Knapps.

b. Demonstrative, sometimes termed mathematical, reasoning. It deals with facts and truths which in their nature are immutable. For instance, space, time, number; in a word, necessary qualities constitute immutable truths; they are termed immutable from the fact that if they are once clearly apprehended as true, they must likewise be so apprehended at all times and by all men.

It is claimed by Reid (Essay on Intellectual Powers) that demonstrative reasoning may enter the field of metaphysics as well as that of mathematics; and by Professor Scott (Elements of Intel. Phil.) that it may also enter the realm of physics.

Further distinctions between probable and demonstrative reasoning may be stated thus: Demonstrative reasoning examines but one side of a sub

ject; probable reasoning must look at all sides. The demonstrative admits of no degrees; but the probable, as to its force in producing assurance, depends upon the weight of evidence. The demonstrative is a chain from which, whatever its length, no link can be spared; the probable is a combination of independent arguments, to which others at pleasure can be added, and from which previously employed arguments may be either dropped or modified. Lastly, demonstrative reasoning requires one to guard especially against mistakes arising from the evidence; while probable reasoning requires one to guard especially against personal prejudice and false definitions.

A moment's reflection will make it clear to every person that there are other facts than those which form the basis of probable and demonstrative reasoning; they are facts rather which are neither contingent nor variable; nor are they generally classed among immutable truths, as are those facts which form the basis of demonstrative reasoning. Hence we make a third class, under:

c. Divine reasoning. It is that reasoning which is based upon the inspirations by the Holy Spirit. When the inspiration is established and the record verified, the truth is absolute; the conclusions reached will not be probable, but will be certain; they will not appear so much like a demonstration, as like an overwhelming and convincing announcement. This mode of reasoning is, as Stier calls it, "a spiritual logic," and as Chrysostom styles it, “inspired logic."

The study of the sacred writers, better than any other course, will illustrate the peculiarities of this kind of reasoning. It often seems foolish to the world, as did Paul's reasoning concerning the cross to the Greek philosophers (1 Cor. i. 23.) "Paul of Tarsus," says Longinus the sophist, "was the first, within my knowledge, who put forth his opinion without supporting it by argument." Still, this same Longinus adds Paul's name to the list of the eight Greek orators "who are the glory of all eloquence."

The aim of this spiritual and peerless logic is not so much to convince as to illustrate and impress ; while the power of the method is found in its sweeping and fundamental deductions. It is never illogical, but frequently rises above ordinary logical methods, using them or dismissing them at pleasure. "The sacred writers often in a concealed syllogism begin with the minor proposition, and in an enthymeme leave us to supply the consequences; now they use several mediums of argument, and then suddenly break into rhetorical interrogations, exclamations, and amplifications."

The following examples taken from our Lord's reasoning will still further illustrate these statements : Matt. v. 34-36, 45, 46; vi. 7, 8, 19-21; vii. 12; ix. 12, 13; xii. 3, 6–8, 11, 12; xvi. 2-4; xix. 3-6; xxiii. 16-22: Mark ii. 19, 20, 27; iii. 4, 23-27; viii. 34-36; xii. 26, 27: Luke v. 36-39; xi. 11-13, 19, 20; xii. 15, 54-57; xiii. 15, 16: John x. 35.

(2) Reasoning classified as to its rhetorical form.