Can Change the World Again.
A SYSTEM OF MENTAL PHILOSOPHY. 1882.
REV. ASA MAHAN, D. D. LL.D.
LAWS OF INVESTIGATION.
INVESTIGATION AND REASONING DISTINGUISHED.
One department of inquiry of great importance still remains. When we have done with this, our inquiry in regard to the intellectual powers will have closed, except as far as we may find their operations combined with that of the other faculties or susceptibilities of the mind.
The department to which I refer, is the employment of these powers in what is called a process of investigation and reasoning. These processes, though intimately connected, are entirely distinct, and should be carefully distinguished the one from the other. In the former process our exclusive object is the discovery of truth. In the latter, the object equally exclusive is, to prove the truth already discovered.
Your attention in the present chapter will be directed to the first process. Our inquiry is, What are the laws which govern the mind, or ought to govern the mind, in a process of investigation of truth?
SUBSTANCES, HOW KNOWN.
All substances are revealed to us by their respective phenomena. Their existence, not only, but their nature, character and powers, are revealed to us in this manner, and this manner exclusively The induction of phenomena therefore lies at the basis of all our investigations pertaining to substances.
INDUCTION OF PHENOMENA, FOR WHAT PURPOSES MADE.
There are four purposes entirely distinct, for which an induction of phenomena is made:
1. For the purpose of discovering the nature, characteristics, and powers of some particular substance.
2. For the purpose of classification, into genera and species.
3. For the purpose of discovering some general fact, or order of sequence.
4. For the purpose of discovering universal laws, in conformity to which the action of substances is subordinated.
Now the principles which should guide us in the induction of phenomena depend upon the objective we have in view in such induction.
INDUCTION PERTAINING TO PARTICULAR SUBSTANCES.
In the induction of phenomena for the purposes of determining the characteristics and powers of some particular substance, the following principles are of fundamental importance in guiding our investigations.
1. In marking the phenomena which appear, or the characteristics of particular phenomena, omit none which do exist, and suppose none which do not exist.
2. In determining the particular powers of the substance in the light of phenomena thus classified and characterized, undeviatingly adhere to the following principles. Phenomena which are in their fundamental characteristics alike, suppose similar powers. Phenomena which are in their fundamental characteristics unlike, suppose dissimilar powers. In strict conformity to those principles, an attempt has been made, in a preceding part of the present treatise, to determine, among other things, the different functions of the human intelligence. Whether the effort has been successful, time will determine.
INDUCTION FOR PURPOSES OF CLASSIFICATION INTO GENERA AND SPECIES.
In the induction of phenomena for the purposes of classification into genera and species, the following principles should be strictly adhered to:
1. Fix definitely and distinctly upon the principle of classification, whatever it may be.
2. With a rigid regard to principle, range with the given class every object, whatever its diversities in other respects, which bears the characteristic mark.
3. Strictly exclude from the class every individual in which the characteristic mark is wanting.
The correctness and apparently easy application of the above principles are so obvious, that it would seem, that every one would find it very easy to apply them in all cases. But their rigid application, in cases where it is often most demanded, requires an intellectual integrity, and sternness of virtue, which the mass of mankind "very little wot of." Every one almost would readily apply them to shells, and rocks, and earths, and beasts, and fowls, and fishes, and even to the objects in the firmament above us. But let us suppose that an individual has before him a correct definition of treason, murder, theft, and of kindred crimes punishable by the law, and that he should discover upon an only son, a dark spot, which, if carefully examined, would mark him as a subject of one of the crimes above named; it would require the stern virtue of a Brutus, to be willing to have inquisition made according to the principles of immutable justice. Cases which thus try the virtue of mankind are of very frequent occurrence.
FINDING A GENERAL FACT, OR ORDER OF SEQUENCE.
A general fact, as we have seen, is a quality which attaches itself to each individual of a given class. Sometimes it may be peculiar to this one class; sometimes it may be common to it and other classes. In other instances, it may he an essential quality of one class, and a mere accident in connection with another. When we have asscertained a fact to be general, if an individual of a given class appears, we know, without particular investigation, that the quality is also present. In determining the question whether a fact is strictly general, the only difficulty which presents itself, is in distinguishing between an essential and in accidental quality. These two principles should determine our conclusions under such circumstances:
1. The existence or absence of perfect uniformity of experience.
2. Experience in such decisive circumstances, as to render it certain, that the fact is, or is not, an essential, and not an accidental quality of the class. Nothing but good judgment can enable one to distinguish between decisive and indecisive facts under such circumstances.
One of the most fruitful sources of error is based upon uniformity of experience in certain circumstances. The absence of such uniformity is certain evidence, that a fact has an accidental, and not a necessary connection with a certain class. Its presence, however, may constitute no certain ground for the opposite conclusion. The king of Japan, for example, reasoned very inconclusively, from an experience perfectly unvarying in his circumstances, to the conclusion, that water never, under any circumstances, exists in any other than the fluid state. To separate the decisive from the indecisive, and rest our conclusions upon the former class of facts only, is the distinguishing characteristic of strong perceptive powers associated with good judgment.
THE PROBABLE AND IMPROBABLE.
Between the perfectly certain and uncertain lie the probable and improbable. If, as has been already said, a fact has been ascertained to have a necessary connection with a given class, its presence, when any individual of the class is met with, becomes perfectly certain. But if its connection is accidental, its existence in connection with a particular individual of the class becomes probable or improbable in proportion to the uniformity or want of uniformity of experience under similar circumstances. Many of the most serious transactions of life rest upon a calculation of probabilities.
ORDER OF SEQUENCE.
The object of investigation here is to ascertain, in reference to given effects, those things which sustain to such effects the relation of real causes. The difficulty to be overcome, often consists in this. The real cause of a given effect may exist in connection with such combinations of powers, that it may be difficult if not impossible for the beholder to determine which produced it. Under such circumstances, careful experiments, in connection with close observation, can alone determine the real order of sequence. There are four important principles which should be strictly adhered to, as tests of all our conclusions in relation to such investigations:
1. When in each experiment, the combination has been different, with this exception, that one element has been present in all, and the given effect has in each instance arisen, we then conclude that this element is the real cause of the effect.
2. When, on the removal of a certain element, the given effect disappears, while it remains, this being present, when each of the others is removed, we then conclude, that this particular element is the particular cause.
3. When the given effect is the invariable consequent of the addition of a new element to a given combination, while the effect does not appear when this antecedent is not added, we then fix upon this particular antecedent as the real cause.
4. When a number of consequents exist in connection with a number of antecedents, and when a particular consequent invariably disappears on the removal of a given antecedent, we fix upon the latter as the real cause of the former.
THE DISCOVERY OF UNIVERSAL LAW.
In the induction of phenomena for the discovery of universal law, three important principles are to be strictly adhered to.
1. The phenomena must not merely consist with this particular hypothesis, but demand it as their logical antecedent.
2. Consequently such phenomena must contradict, with equal positiveness, every other contradictory hypothesis.
3. All phenomena to which the given hypothesis does not sustain the relations of logical antecedent, must be left wholly out of the account, as having no bearing upon the subject.
But this subject has been so fully treated of in the preceding chapter, that nothing further upon it is demanded here.
It often happens, and that in reference to subjects of the greatest importance, that the facts which constitute the basis of our inquiries after truth, have never been given to us as objects of sense or consciousness. We are compelled to receive or reject them on the testimony of others. From this source, the greatest part of our knowledge, and of the most important of our knowledge, is derived.
The great inquiry here presents itself: What are the laws of evidence under the influence of which we judge ourselves bound to receive and act upon the phenomena revealed to us through the affirmations of other minds? Testimony is used for the same purpose that the faculties of sense and consciousness are used; to wit, for the ascertainment of facts, or phenomena, which constitute the basis of judgment in regard to a given subject.
CHARACTERISTICS OF THE STATEMENTS MADE BY A WITNESS.
The statements made by a witness may be contemplated in three points of light.
1. In the light of the idea of possibility or impossibility. If an individual should affirm that an idiot, remaining such, had given a scientific demonstration of some of the most abstruse problems in the higher mathematics, we should give no credit at all to his statement, on the ground of a perceived impossibility of the occurrence of such a fact. If, on the other hand, the witness should affirm that an individual remaining an idiot up to a certain period, did, from that period, manifest a high degree of mental energy, we should pronounce the statement highly improbable, though not absolutely impossible in itself. The statement, therefore, is capable of being established by testimony.
2. The statement may also be contemplated in reference to the question whether in itself, aside from the character of the witness, it is credible or incredible. A statement characterized as impossible, is absolutely incredible. No weight of testimony can render it worthy of belief. An event also may be contemplated as possible, and yet the statement that it has actually occurred may be almost wholly wanting in respect to credibility. If it should be said that a pure spirit before the throne had, without any form of temptation from without or within, violated his duty to his God, we should hesitate to pronounce the occurrence impossible in itself. Yet we should deem it hardly credible. A statement, to be credible, must assert what is in itself perceived to be possible. It must also fall within the analogy of experience. Thus, to the great mass of mankind, there is wanting entirely any experience of a direct revelation from God. Yet the existence of such a revelation for the good of the race, is analogous to what all have experienced of the divine beneficence to man. There is, therefore, nothing incredible in the statement, that such a revelation has been made. A statement, then, which affirms the occurrence of an event in itself possible, and which falls within the analogy of experience, is capable of being rendered worthy of all confidence by testimony.
3. A statement is in itself probable or improbable, when it does or does not accord with general experience in similar circumstances. A thing may be possible, and, at the same time, very improbable. No one would say that is absolutely impossible that a die, when thrown, should fall twenty times in succession with the same number uppermost. Yet all would pronounce such an occurrence in an extreme degree improbable. An improbable event may be rendered worthy of belief by testimony. A much higher degree, however, is demanded to establish such an occurrence, than one which accords with what we have had experience of in similar circumstances.
CIRCUMSTANCES WHICH GO TO ESTABLISH THE CREDIBILITY OF A WITNESS.
We will now consider the circumstances which go to establish the credibility of a witness. Among them, I will specify the following, without enlarging upon any of them.
1. The most important characteristic is a character for veracity.
2. The next is a capacity to comprehend the particular facts to which he bears testimony.
3. Full opportunity to observe the facts, together with evidence that adequate attention was given to them at the time.
4. Evidence that the occurrence was of such a nature that the individual was not deceived at the time, and that it sustains such a relation to the individual, as to preclude the reasonable apprehension that his memory has failed him in respect to it.
5. An entire consistency between the statements of the witness and his conduct in respect to the events, the occurrence of which he affirms. If an individual affirms his entire confidence in the veracity of a certain person, and his entire treatment of him is in full harmony with his statements, we are bound to admit the truth of what the witness testifies in relation to his own convictions.
CORROBORATING CIRCUMSTANCES ASIDE FROM THE CHARACTER OF THE WITNESS.
But there are circumstances often attending the testimony of a witness, totally disconnected with the question of his veracity, which demand our confidence. Among these, I specify the following:
1. The entire absence of all motives to give false testimony. This principle is based upon the assumption, that men do not act without some motive, and that consequently they will not ordinarily violate the principles of truth without some temptation to do it.
2. When no assignable motives exist to induce an individual to make a given statement, if he is not convinced of its truth, and when strong motives impel him to deny it, especially if it is false, then we recognize ourselves as obligated to believe his statements without reference to his moral character at all.
3. Another circumstance which tends strongly to corroborate the statements of a witness is this: When the facts affirmed lie along the line of our own experience in similar circumstances. This, however, is not a safe principle to rely upon, in the absence of other circumstances of strong corroboration. Villains often throw their statements into harmony with experience, for the purpose of covering their dark designs.
4. When, though new, they accord with the known powers of the agent to whom they are ascribed.
5. When these facts stand connected with the development of laws and properties in the agent, before unknown.
Under such circumstances, the further removed from experience the facts are, the greater the probability of their being true, because of the greater probability that they would, if not true, have been unknown to the witness.
The confidence which we repose in the affirmations of a witness is greatly strengthened by the concurrent testimony of other individuals. Here the following circumstances should be especially taken into the account:
1. When each witness possesses all the marks of credibility above referred to.
2. When there is an entire concurrence in their statements, or a concurrence in respect to all material facts.
3. When the characters of the several witnesses are widely different,as friends and enemies, etc., who of course must be influenced by widely different motives, and even by those directly the opposite; especially when their characters, motives, and relations to the subject are so different as to preclude the supposition of a collusion between the witnesses.
4. When one witness states facts omitted by others, and when all the statements together make up a complete account of the whole transaction.
5. When there are apparent contradictions between the statements of the witnesses, which a more enlarged acquaintance with the whole subject fully reconciles. Such occurrences in testimony preclude the supposition of collusion, and present each individual as an independent, honest witness in the case.
6. Coincidences often occur in the statements of witnesses which, from the nature of the case, are manifestly designed. When such occurrences attend the testimony of various individuals, all affirming the same great leading facts, they tend strongly to confirm the testimony given. This principle is most beautifully illustrated by Dr. Paley, in his Horae Paulinae:a work deserving more attention than almost anything else which the Doctor ever wrote.
Great care and sound judgment are requisite in the application of the principles above stated. When they are fulfilled in the case of testimony pertaining to any subject, it would be the height of presumption and moral depravity in us not to act upon it as true. Infinite interests may be safely based upon the validity of such testimony. We are often necessitated to decide and act, however, in the absence of testimony thus full and complete, and often upon testimony failing, in many respects, of the marks of credibility above laid down. To discern between the valid and the invalid, to determine correctly when to trust and when to withhold confidence, requires stern integrity of heart, and a judgment, "by reason of use exercised," to distinguish the true from the false.