LECTURE VI.

INSIGHT AND REASONING.

Man's knowledge evidently began with the observation of external objects and reflections concerning them. At a later stage, I presume, his thoughts would be occupied with the facts of consciousness, the thoughts and feelings that occur within. Different theories and opinions would be expressed; and then some test of truth would be seen to be necessary. And at last, thoughtful men would reach the ultimate question as to the nature and foundation of knowledge. In ancient Greece this question seems to have been first distinctly answered by Plato, 374 or 380 B. C. At any rate he attempted a solution of the question that has remained as the starting point for all subsequent ones.

1. The Nature of Knowledge.

In order to any intelligent discussion of the subject it will be necessary to make some preliminary statements concerning the view in regard to the character of knowledge which all these discussions assume. And this assumption has always, so far as I know, been made without any distinct explanation or justification anywhere.

Knowledge is assumed to consist-or at least it has been

treated as if consisted of certain elementary facts or atoms, called "ideas," "notions," "conceptions," or "concepts.” These ultimate elements or atoms, are expressed by words and may be expressed in, all cases by nouns. Thus in the case of iron," for example, we know the word, then the thing, and finally the notion or idea of the thing. The idea, or conception, represents the thing, the word denotes it.

2. The Relation of Words to Ideas.

It is not supposed, however, that there is any resemblance or likeness between the ideas and the things, any more than there is between the word and the thing. But while, however, the word denotes the thing by an arbitrary agreement and consent among mankind, there is supposed to be some sort of a different relation between the idea of the thing and the thing itself. The word "iron" is in no way like the thing iron. The relation is purely arbitrary, and the two are associated so that the one suggests the other only by habit and common usage. In regard to the thing iron and our idea of it, the case is somewhat different. The relation is not supposed to be arbitrary, or the result of choice at all. It is thought to be beyond our control, so that at the sight of the object an idea will be produced, which is the same in all minds, and is thus the basis of the common understanding among men. The words denoting iron may be endlessly varied, differing in every language and dialect spoken by man, and yet the idea that represents it to the mind, will be the same for all; just as the sensation of pain produced by the prick of a thorn, for example, will be the same in all men, however unlike the thorn itself, and however unlike the words that may be used to denote it.

3. Ideas and Affirmations.

If now we pass from words-nouns for the most part—which

express our ideas and denote the things which our ideas represent, to sentences, which express judgments and make assertions concerning the things, we find that the union of any two ideas makes a sentence or affirmation. The proposition, sentence or affirmation, presupposes two ideas, and an act of the mind affirming a relation between them. Thus if I say "iron "is hard," we are supposed on this theory, to have the two "ideas," one representing " iron," and the other hardness." And it is the province of logic to show how ideas, represented by words, may be combined into propositions, syllogisms and processes of argumentation. But any statement of fact or of opinions, any form of inference or argument, any construction of a theory or hypothesis, is but the synthesis or putting together, in various ways, of the primary particles or atoms of knowledge, called, as before said, ideas, notions, conceptions, etc.

Hence any account of the origin of knowledge must account for and explain the origin of these elements of knowledge in the mind.

4. Four Kinds of Propositions.

Sentences, for the purposes now before us, may be referred to four classes. Technically we call them propositions. And in their simplest form they are equivalent to S is P. "Iron is "hard;" where "iron" is the subject spoken of, "hard" or "hardness" the predicate affirmed of it.

(1.) If the predicate is an idea, which is seldom and only occasionally associated with the subject, the proposition is regarded as accidental; and the subject is usually limited by an article, pronoun or something of the kind, as "this man is sick," as the idea of "sickness" is not always associated with

man.

(2.) If the predicate denotes a property which characterizes an individual, the proposition is called an individual proposition, "this apple is yellow," "this horse is red." In this case

the idea of "redness" and that particular horse is always associated, that horse is always red, though perhaps there are but few horses of that color.

(3.) When a predicate is affirmed of a class, the proposition is said to be general, as men are rational beings." Here the idea of men or rather of man, and the idea of rationality are so constantly associated that we affirm the general proposition, affirm rationality of the class or genus, man, although, and notwithstanding, there may be exceptions.

(4.) But again, if the two ideas are so related that the one always implies the other, and they cannot be separated, the proposition is said to be universal or absolute. Thus" iron is "extended." The idea of extension is supposed to be inseparable from the idea of any material substance. Whether mass

or molecule it is supposed to be extended in-and to occupy some part or portion of-space.

Propositions of the first and second kinds make up what is called accidental matter. And they seldom enter into or make any part of Science. Propositions of the third kind, general propositions, make up the Physical and Natural Sciences, while propositions of the fourth kind make up Mathematics, and the a priori principles of all knowledge.

5. Ideas the Ultimate Elements of Knowledge.

But these ideas, notions, concepts; what are they? This is a question of ontology, rather than of psychology. Philosophers are by no means agreed with regard to their nature. It is in fact the opinion of many that they have no nature of their own, that they do not exist as realities, that they are mere objectified abstractions, mere arbitrary assumptions, taken and used for the convenience of discussion, just as in optics we speak of the image, or in geography, of the equator, the meridians, the parallels, etc.

Ideas are not, however, regarded by anybody as objects of

sight or touch. They are not objects that can be imagined, even if they are objects at all.

For imagination, as we have seen, objects must be visible, and limited, visible so as to affect the eye, and limited so as to have outline and form. Hence we can imagine only those objects that are both material and finite. I think we cannot imagine the air, or any gas, without giving it a color. We cannot imagine space, without giving it a limit, an outline and a form, and then it is not space.

their reality do not deThey hold that ideas That they are not

So with ideas, those who believe in scribe them, though they define them. exist only in the mind, that is in some mind. material and cannot be represented to the senses as, in imagination. It is claimed that we are conscious of them in thinking, that in fact they are what "the mind is immediately occu"pied with in thinking," so that we cannot think without them.

At any rate this theory in regard to ideas under one name or another, has entered all languages, and is in fact such a necessity to the discussion of the subject that we can no more dispense with them in talking of psychological and ontological subjects, than we can dispense with the geographical terms already referred to in treating of the shape of the earth, and the situation of the various places and objects on its surface.

6. Plato's Theory of Ideas.

There have been six theories as to the origin of ideas, which it will be well to state briefly before we go any farther.

1. The first is that of Plato, He does not explain or expound his theory in all its parts, and in a scientific way, anywhere in his works.

He claims that ideas are the essence of the Divine Mind; that our souls existed in a previous state before our birth into this world, and that we acquired our ideas there, and conse