The tests of various kinds of truth: being a treatise of applied logic

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UNITED STATES OF AMERICA.

Preface

THE age may be characterized as one of unsettled opinion. Our ambitious youths are not satisfied with the past, its opinions, and practices. Authority is not worshiped by them ; they have no partiality for creeds and confessions. They do not accept, without first doubting, the truths supposed to be long established. In searching into the foundation of the old temples they have raised a cloud of dust and left lying a heap of rubbish. It is an age out of which good and evil, either or both, may come, according as it is guided. We may entertain fears, for it is dancing on the edge of a precipice down which it may fall. We may cherish hope, for it is an inquiring age.

Every form and phase of opinion seeks to have a philosophy, in which it may embody and express itself and by which it maybe defended. Agnostics is the shape or figure which the doubting and hesitating spirit takes. It is not a new heresy. It has been held by a few in every age ; it is now espoused by many, provisionally, till something more solid or

6 Preface.

showy is propounded. It used to be called nescience, which maintains that nothing can be known, and nihilism, which holds that there is nothing to be known. It is of little use trying to argue with it, for it allows us no premises as a ground on which to start, and has no body or substance that we can attack. It is easy to show that it is suicidal. It is an evident contradiction to affirm that we know that we can know nothing. But when we have demonstrated this we have not destroyed it any more than we have killed a specter by thrusting a spear into it ; for its defense is that all truth is contradictory. The best way of dealing with it is to allow it to dance as it may, like the shadows of the clouds, and, meanwhile, to found and build up truth and set it up before the mind, that it may be seen in its own light. It is well known that when we see a solid object through and beyond a specter the specter melts away and disappears. So it will be with agnosticism — it will vanish when we fix our eyes upon the truth.

But meanwhile an immense number and variety of crude views and opinions on the most momentous subjects, such as morality and religion, are set before the young and pressed upon their acceptance. In consequence they often feel a difficulty in knowing what to believe, and they may be led to

Preface. 7

believe too little or too much. In these circumstances it is of vast importance to provide them with tests which may enable them to distinguish between reality and fiction and settle them in the truth.

This is what is attempted in this work, which is meant for those who wish for their own satisfaction to know on what foundation the truths on which they are required to believe rest.

It is hoped that, being a treatise on what Kant calls applied logic, which may be quite as useful as primary or formal logic, and announcing as it does, the laws of Inductive as well as Deductive thought, this work may be profitably used as a text-book in those colleges and upper schools where there is not time or taste to study metaphysics, or the technicalities of Formal Logic, or the full applications of Inductive Logic.

These papers were first delivered and then published as Lectures in Ohio Wesleyan College, on the foundation established by my estimable friend. Dr. Merrick.

CONTENTS,

Introduction

WE have truth when our ideas are conformed to things. The aim of this work is to show that there is truth, that truth can be found, and that there are tests by which we may determine when we have found it. We do not propose to guide inquirers in any particular department of investigation ; this can best be done in introductions to the books and lectures treating of the several branches of knowledge.

Kant and the German metaphysicians have shown again and again that there is no one absolute criterion to settle all truth for us ; that will determine, for example, at one and the same time, whether there is a fourth dimension of space, whether the planet Jupiter is inhabited, where the soul goes at death, and what kind of crops we are to have next year. But it can be shown that there are truths which may be ascertained and that there are criteria which prove when they are so ; and these clear, sure, and capable of being definitely expressed. But the test which settles one truth for us does not neces-

10 Introduction.

sarily settle all others, or any others. It is necessary to distinguish between different sorts of truth, and we should be satisfied when we find a test of each kind. I am convinced that historical, scientific, and logical investigation has advanced so far that we can now enunciate criteria for every kind of truth. The aim of the criteria, it should be noticed, is not so much to help us to discover truth as to determine when we have found it.

LECTURE FIRST.

TRUTHS TO BE ASSUMED.

I

THE mind must start with something. There are things which it knows at once. I know pleasure and pain. I do more: I know myself as feehng pleasure and pain. I know that I am surrounded with material objects, extended and exercising properties. I know, by barely contemplating them, that these two straight lines cannot contain a space. These are called first truths. There must be first truths before there can be secondary ones ; original before there can be derivative ones. Can we discover and enunciate these ? I believe we can.

We are not at liberty, indeed, to appeal to a first principle when we please, or because it suits our purpose. When we are left without evidence we are not therefore allowed to allege that we need no evidence. When we are defeated in argument we are not to be permitted to escape by falling back on what is unproved and unprovable. It is true that we cannot prove every thing, for this would imply an infinite chain of proofs every link of which would hang on another, while the whole would hang on nothing — that is, be incapable of proof. We cannot prove every thing by mediate evidence, but we can show that we are justified in assuming certain things. We cannot prove by any external circumstance that two straight lines cannot inclose a space, but we can show that we are justified in assuming it. We are to " prove all things." But there are some things which have their proof in themselves. We discover it by simply looking at the things. It is thus that we know that we exist ; that the shortest distance between two points is a straight line ; that hypocrisy is a sin. We need no external evidence. The evidence is in the thing; in the very nature of the thing. We do not require mediate, we have immediate proof.

II

This kind of truth is to be distinguished from two others for which we require what is called mediate proof. First, there are cases in which we get this by simply thinking. A truth being allowed we infer something else from it. Thus, being assured that all men are responsible, we argue that heathens, being men, are responsible. Secondly, in other cases we need observation and a gathering of facts, that is induction ; in order to the discovery of a general fact or law. It is thus that we have discovered that a year consists of so many days ; thus that Newton discovered the law of gravitation, and Dalton that of definite proportions in the composition of bodies. These two last kinds of cases, which may be called the logical and inductive, differ from the first, which may be called the metaphysical. In this chapter first truths are treated of; in those that follow, reasoned and observational truths. In all the three our aim is to discover the tests.

III

The evidence of the first class of truths is discovered by what is called Intuition, which looks directly on the objects; the truth is therefore called Intuitive. It is also called First, or Primary, as it is the first in the order of nature and things. It is designated as Fundamental in that it bears up other truths. It is described as Necessary inasmuch as, perceiving the objects directly, we cannot be made to believe otherwise. Since the publication oi Kanfs Kritic of Pure Reason it is more frequently described as a priori in that it is known prior to a gathered experience, the truth discovered by which is called a posteriori. It maybe spoken of as Original, as opposed to what is Derived. These are not the most prominent truths to the ordinary observer ; they lie deep down in the soul ; they are the foundation on which other truths are laid.

They are numerous and varied. Some of them, and these the first and original ones, are cognition of things. Thus we all know body, with its properties, and self or spirit, with its properties. Some of them are beliefs — such as our belief in space and time and in their continuity. From these arise judgments, in which we compare two or more cognitions and beliefs and discover a relation between them. These judgments may be arranged under eight heads. In identity, we declare that it is impossible to be and not to be at the same time. In comprehension, we declare that the whole is equal to the sum of its parts. In resemblance, we affirm that what is true of a class must be true of all the members of the class. We know that body is in space. We know that all events happen in time. In quantity we are sure that equals added to equals are equals. In contemplating things as acting we maintain that every property implies a substance. When we see an effect we are sure that it has had a cause. These are intellectual cognitions, beliefs, and judgments. But we have also primary moral convictions. We know at once the distinction between moral good and evil ; we declare love to our neighbors to be a virtue binding upon us, and we need no one to argue with us to convince us that to tell a lie or cheat our neighbor is evil.

IV

These primitive convictions run through our thoughts, ideas, and acts. Every man acts upon them. We are sure that we exist and that we have a body, extended, and acting on us and other objects. We know that we are the same persons to-day that we were yesterday. The creditor, when he receives only part of what is owing him, tells his debtor that this is less than the whole. When a man knows that spring, summer, autumn, and winter make up the seasons he expects when the three first are past that winter is coming. A farmer does not propose to inclose a field by two straight fences. When we awake from sleep we are confident that we have been alive all the time since we fell asleep. The clerk in his calculations acts on the principle that equals subtracted from equals are equals. When we see a body we are convinced that it has properties. When we see a house on fire we are sure it has been ignited. The circumstance that all men act upon these principles led the Scottish school of metaphysicians to call them principles oi common sen.se.

V

We may assume all such truths. They do not need proof. A man who would seek it must be beside himself. He may be compared to one going out with a taper to see the sun. These truths shine in their own light. We may use them in all our thoughts and inquiries and in all our arguments with our fellow-men, provided we properly enunciate them.

A man had better assume his own existence. He might find it difficult to establish it by argument. But if he is determined, by all means let him try it ; he will only be impressed the more with the impossibility of his doing it. How will he do it ? To what will he appeal ? How will he begin ? With the testimony of his neighbors ? He will find that he has clearer proof of his own existence than of that of his neighbor, and that he cannot prove the existence of his neighbors till he first assumes his own. It is the same with all other self-evident truths. We cannot prove them by other truths, but we may use them to prove other truths.

VI

Let us seek to determine precisely the nature of these truths. They may be viewed under three aspects — aspects of one and the same thing.

1. They are Perceptions of Things. We perceive that body is extended, and that it exercises properties, such as resistance to our energy and to other bodies. We are conscious of self as thinking and feehng. We believe that space and time extend beyond what we observe of them. We decide at once that contradictions cannot both be true ; that the abstract implies the concrete ; that universals imply singulars ; that we cannot be both here and in China at the same time ; that two halves make up the whole ; that properties imply a substance ; that a change is produced by an adequate power. We look on self-sacrifice, for a good cause, as good, and treachery as an evil. All these perceptions are direct, and are in consciousness.

2. They are Regulative Principles. I do not believe that there is any such thing as innate ideas. Locke exploded them forever. But the mind of the child is not altogether a nonentity or a blank. It has powers or capacities ready to be exercised on the appropriate objects being presented. These are in the mind as gravitation lies in matter, as life remains in the seed all winter, as seeds have remained, with life in them, in the tombs of Egypt for thousands of years.

Mr. Mill has shown that all the powers in nature

are tendencies. They tend to act according to 2 their nature. Thus oxygen tends to join in definite proportions with hydrogen to form water ; bodies attract other bodies to them inversely according to the square of the distance. Our ideas tend, unless interfered with by external objects, to follow each other in a certain order ; when two ideas have been in the mind together, the one tends to cull the other, and like suggests like. In much the same way the powers of intuition abiding in the mind ever tend to act, and are called forth by objects. In a sense, they so far direct and control the mind. Of the principle we are not conscious, but we are conscious of its exercises, which are the perceptions of which I have been speaking under last head.

3. They may become Axioms. All the perceptions of which I have been discoursing are in the first instance singular or individual, and not abstract or general. We do not say of every two straight lines that they cannot inclose space, but of these two straight lines before us that they cannot inclose a space. We do not at first announce that all men are responsible, but of ourselves or some other person that he is responsible. I do not formally proclaim the metaphysical principle, every effect has a cause, but of this particular effect, the burning of a rick of hay, that it has had a cause. But then we can generalize our individual perceptions. We see that what is true of the object or case before us is true of the same object or cases every-where and in all places. We now reach general maxims true of the objects at all times and in all circumstances. Fraud cannot be good on the planet Earth, or the planet Jupiter, or the dog-star Sirius. Parallel lines, we see, will never meet in earth, or star, or the space beyond. We have now such axioms as those of Euclid. We have moral maxims such as the Ten Commandments, and the precepts in the Sermon on the Mount.

VII

But what we have specially to do here is to enumerate the criteria by which such truths may be tried, and which will settle for us whether we are entitled to assume without any mediate proof what may be presented to us by ourselves or others for our acceptance.

Self-evidence is the primary test of that kind of truth which we are entitled to assume without mediate proof. We perceive the object to exist by simply looking at it. The truth shines in its own light, and, in order to see, we do not require light to shine upon it from any other quarter. We are conscious, directly, of self as understanding, as thinking, or as feeling, and we need no indirect evidence.

Thus, too, we perceive by the eye a colored surface, and by the muscular touch a resisting object, and by the moral sense the evil of hypocrisy. The proof is seen by the contemplative mind in the things themselves. We are convinced that we need no other proof. A proffered probation from any other quarter would not add to the strength of our conviction. We do not seek any external proof, and if any were pressed upon us we would feel it to be unnecessary — nay, to be an encumbrance, and almost an insult to our understanding.

But let us properly understand the nature of this self-evidence. It has constantly been misunderstood and misrepresented. It is not a mere feeling or an emotion belonging to the sensitive part of our nature. It is not blind instinct, or a belief in what we cannot see. It is not above reason or below reason ; it is an exercise of primary reason prior, in the nature of things, to any derivative exercises. It is not, as Kant represents it, of the nature of a form in the mind imposed on objects contemplated and giving them a shape and color. It is a perception, it is an intuition of the object. We inspect these two straight lines, and perceive them to be such in their nature that they cannot inclose a space. If two straight lines go on for an inch without coming nearer each other, we are sure they will be no nearer if lengthened millions of miles as straight lines. On contemplating deceit we perceive the act to be wrong in its very nature. It is not a mere sentiment such as we feel on the contemplation of pleasure and pain ; it is a knowledge of an object. It is not the mind imposing or superinducing on the thing what is not in the thing ; it is simply the mind perceiving what is in the thing. It is not merely subjective, it is also objective — to use phrases very liable to be misunderstood ; or, to speak clearly, the perceiving mind (subject) perceives the thing (object). This is the most satisfactory of all evidence ; and this because in it we are immediately cognizant of the thing. There is no evidence so ready to carry conviction. We cannot so much as conceive or imagine any evidence stronger.

Necessity is a secondary criterion. It has been represented by Leibnitz and many metaphysicians as the first and the essential test. This I regard as a mistake. Self-evidence comes first, and the other follows and is derived from it. We perceive an object before us and know so much of its nature ; and we cannot be made to believe that there is no such object, or that it is not what we know it to be. I demur to the idea so often pressed upon us that we are to believe a certain proposition because we are necessitated to believe in it. This sounds too much Hke fatahty to be agreeable to the free spirit of man. It is because we are conscious of self that we cannot be made to believe that we do not exist. The account given of the principle by Herbert Spencer is a perverted and a vague one : all propositions are to be accepted as unquestionable whose negative is inconceivable. This does not give us a direct criterion as self-evidence does, and the word inconceivable is very ambiguous. But necessity, while it is not the primary is a potent secondary test. The self-evidence convinces us ; the necessity prevents us from holding any different conviction.

Catholicity or Universality is the tertiary test. By this is meant that it is believed by all men. It is the argument from catholicity, or common consent — the sensus communis. All men are found to assent to the particular truth when it is fairly laid before them, as, for instance, that the shortest distance between two points is a straight line. It would not be wise nor safe to make this the primary test, as some of the ancients did. For, in the complexity of thought, in the constant actual mixing up of experiential with immediate evidence, it is difficult to determine what all men believe. It is even conceivable that all men might be deceived by reason of the deceitfulness of the faculties and the illusive nature of things. But this tertiary comes in to corroborate the primary test, or rather to show that the proposition can stand the primary test which proceeds on the observation of the very thing, in which it is satisfactory to find that all men are agreed.

Combine these and we have a perfect means of determining what are first truths. The first gives us a personal assurance of which we can never be deprived ; the second secures that we cannot conquer it ; the third, that we can appeal to all men as having the same conviction. The first makes known realities ; the second restrains us from breaking off from them ; the third shows us that we are surrounded with a community of beings to whom we can address ourselves in the assurance of meeting with a response. The first is the most satisfactory, as it brings us closest to things. The second is the most definite and decisive, as it admits of no denial. The third brings us into closest relationship with our fellow men and gives us confidence in addressing them. The three constitute a treble cord which cannot be broken.

It should be noticed that these tests apply not only to our primitive knowledge but to our primitive beliefs. We have such beliefs. We believe in the existence of things which we cannot know by the senses, which we cannot see or hear, smell or taste or touch. We believe in space and time as stretching away beyond our ken. We believe in the infinite, though we may not be able fully to comprehend it. Our beliefs require to be tested fully and as much as our knowledge. A large number of men and women, even some who are shrewd and wise, are apt to cherish fancies which have no realities corresponding to them. There are classes of people who are particularly addicted to such visions. You hear them say, " I feel this to be true. I must believe it." A more cultivated set of people tell you this is so interesting that I must cleave to it. There are numbers thus led into great extravagances of credence which expose them to ridicule or land them in folly, or, it may be, in very serious errors or mistakes.

Now there is a method of keeping people from being allured into bogs by these will-o'-wisps. We are to try the spirits whether they are of God. We have a reliable means of trying them. We may, we should, inquire whether what we are invited to assume is self-evident truth and not a mere fancy ; whether we are necessitated to believe it as we look at the things, or whether we may not be led to adopt or reject it by the wishes of the heart ;

whether it is held by man as man, or merely by people with idiosyncrasies and prejudices. Our feelings were never meant to be the tests of truth, though they may prompt us to seek it, may irradiate it so as to make it more attractive, and instil life into the soul and thereby prompt to action.

It is to be admitted that there is a mysticism which is very fascinating and at times elevating, as, for instance, in the pages of Thomas a Kempis. But it may be delusive, and the error may be accepted along with the truth. We may, by the criteria I have announced, get all the good without the accompanying evil ; we may root out the weeds, that the flower and fruit-bearing plants may flourish the better. The tests clear away the mists that we may have a full view of the beauties of the sky and landscape.

It will be understood that what is offered in this lecture does not profess to be the whole of knowledge ; it is only primary knowledge. A far greater number and variety of truths are reached in other ways than by intuition, while, however, they always presuppose it. Yet only the foundation-stones have been laid — I hope, as the Free Masons say, that " this foundation is well laid," that it is " a sure foundation." The mature tree is not yet before us ; only a few seeds have been sown and some roots planted, which are well "rooted and grounded." These primitive truths, like the granite rocks, go down deepest into the earth and mount the highest toward heaven. They bind and guarantee all other truths. They give us what no other powers can, which sense cannot give nor understanding give — eternal truths and eternal morality. They look as if they were the very footstool of God, before which we bow and put up our petitions for further instruction to him who sitteth upon the throne.

Note. — The above is a compend of Metaphysics or the Science of First Truths. The science is expounded fully in my work on " First and Fundamental Truths."

Discursive or Deductive Truth. 2V

Chapter Second. Discursive Or Deductive Truth

I.

WE have seen what are the truths with which every mind starts. We are now to view it as adding to the stock. It may do so in two ways. It may by its own power, or by a gathered observation of facts. In this lecture I am to treat of the first of these methods.

The process by which this end is accompHshed is discursive or deductive ; that is, we proceed from a truth given or allowed to something else implied in or deduced from it. It being granted that all men are mortal, we at once conclude that this man and that man and that we ourselves must die.

What is admitted is called the premise or premises. These may be got from one or other of two quarters : from intuition — that is, immediate inspection of things — or from induction, that is, from a gathered collection of facts. The first of these has been expounded in last lecture, the other will be unfolded in the lectures which follow.

We pre-suppose, then, that the mind has got certain facts allowed it as premises. These may be intuitive or inductive ; one or both. In looking at these we discover that certain truths are involved in them and may be legitimately drawn from them. In this chapter I am to unfold the process by which this end is accomplished, to determine the laws, their extent, and their limits.

The discursive process is usually described as consisting of three elements — the Notion, Judgment, and Reasoning. There is the notion, which, when expressed in language, is the term. There is judgment, which, when expressed, is the proposition. There is reasoning, which, when put in words, is the argument. By means of each of these we reach derivative truth, which may be rigidly tested.

Logic is the science which treats of discursive thought. I am not, in this little work, to give a system of logic. I use logic simply as furnishing the criteria by which deductive truth may be tried.

The grand regulating principle of all discursive thought is that what is drawn from the premise or premises must be in the premises. Being there, and being seen to be there, we draw it out. But we must take care that what we bring out is in what we have derived it from. This law, rigidly carried out, will preserve us from all inconclusive reasoning. We cannot draw light from cucumbers, because there is no light in the cucumber. But, it being allowed us that all men have a conscience, we infer that this liar, though he has not obeyed it, has a conscience. This general rule may be applied to every kind of deduction or discursive thought, and, taken along with other and more minute rules founded on it, decides for us whether we are proceeding on the laws of thought, which, being planted or developed in our nature by God, are always truthful and authoritative. Each of the two great processes will be found to have its own laws.