Criminal Psychology

Hans Gross

Part 4

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Evidently the finding of causes involves, according to the complexities of the case, a varying number of subordinate tasks which have to be accomplished for each particular incident, inasmuch as each suspicion, each statement pro or con has to be tested. The job is a big one but it is the only way to absolute and certain success, provided there is no mistake in the work of correlating events. As Sch.e.l.l says: "Of all the observed ident.i.ties of effect in natural phenomena only one has the complete strength of mathematical law--the general law of causation. The fact that everything that has a beginning has a cause is as old as human experience." The application of this proposition to our own problem shows that we are not to turn the issue in any unnecessary direction, once we are convinced that every phenomenon has its occasion. We are, on the contrary, to demonstrate this occasion and to bring it into connection with every problem set by the testimony at any moment. In most cases the task, though not rigidly divided, is double and its quality depends upon the question whether the criminal was known from the beginning or not. The duality is foremost, and lasts [1] Cf. S. Strieker: Studien ber die a.s.soziation der Vorstellungen. Vienna 1883.

longest if only the deed itself is known, and if the judge must limit himself entirely to its sole study in order to derive from it its objective situation.

The greatest mistakes in a trial occur when this derivation of the objective situation of the crime is made unintelligently, hastily or carelessly, and conversely the greatest successes are due to its correct rendering. But such a correct rendering is no more than the thoroughgoing use of the principle of causality. Suppose a great crime has been committed and the personality of the criminal is not revealed by the character of the crime. The mistake regularly made in such a case is the immediate and superficial search for the personality of the criminal instead of what should properly proceed--the study of the causal conditions of the crime. For the causal law does not say that everything which occurs, taken as a whole and in its elements, has one ground--that would be simply categorical emptiness. What is really required is an efficient and satisfying cause. And this is required not merely for the deed as a whole but for every single detail. When causes are found for all of these they must be brought together and correlated with the crime as described, and then integrated with the whole series of events.

The second part of the work turns upon the suspicion of a definite person when his own activity is interpolated as a cause of the crime. Under some conditions again, the effect of the crime on the criminal has to be examined, i. e., enrichment, deformation, emotional state, etc. But the evidence of guilt is established only when the crime is accurately and explicitly described as the inevitable result of the activity of the criminal and his activity only. This systematic work of observing and correlating every instant of the supposed activities of the accused (once the situation of the crime is defined as certainly as possible), is as instructive as it is promising of success. It is the one activity which brings us into touch with bare perception and its reproduction. "All inference with regard to facts appears to depend upon the relation of cause to effect; by virtue of this relation alone may we rely upon the evidence of our memories and our senses."[1] Hume ill.u.s.trates this remark with the following example: If a clock or some other machine is found on a desert island, the conclusion is drawn that men are or were on the island. The application is easy enough. The presence of a clock, the presence of a three-cornered wound is perceived by the senses--that men were there, that the wound was made with a specific kind of in- [1] Meinong: Humestudien. Vienna 1882.

strument, is a causal inference. Simple as this proposition of Hume's is, it is of utmost importance in the law because of the permanent and continually renewed problems: What is the effect in *this case? What is the cause? Do they belong together? Remembering that these questions make our greatest tasks and putting them, even beyond the limit of disgust, will save us from grave errors.

There is another important condition to which Hume calls attention and which is interpreted by his clever disciple Meinong. It is a fact that without the help of previous experience no causal nexus can be referred to an observation, nor can the presence of such be discovered in individual instances. It may be postulated only. A cause is essentially a complex in which every element is of identical value. And this circ.u.mstance is more complicated than it appears to be, inasmuch as it requires reflection to distinguish whether only one or more observations have been made. Strict self-control alone and accurate enumeration and supervision will lead to a correct decision as to whether one or ten observations have been made, or whether the notion of additional observations is not altogether illusory.

This task involves a number of important circ.u.mstances. First of all must be considered the manner in which the man on the street conceives the causal relation between different objects. The notion of causality, as Schwarz[1] shows, is essentially foreign to the man on the street. He is led mainly by the a.n.a.logy of natural causality with that of human activity and pa.s.sivity, e. g., the fire is active with regard to water, which simply must sizzle pa.s.sively. This observation is indubitably correct and significant, but I think Schwarz wrong to have limited his description to ordinary people; it is true also of very complex natures. It is conceivable that external phenomena shall be judged in a.n.a.logy with the self, and inasmuch as the latter often appears to be purely active, it is also supposed that those natural phenomena which appear to be especially active are really so.

In addition, many objects in the external world with which we have a good deal to do, and are hence important, do as a matter of fact really appear to be active--the sun, light, warmth, cold, the weather, etc., so that we a.s.sign activity and pa.s.sivity only according to the values the objects have for us. The ensuing mistake is the fact that we overlook the alternations between activity and pas- [1] Das Wahrnehmungsproblem von Standpunkte des Physikers, Physiologen und Philosophen. Leipzig 1892.

sivity, or simply do not make the study such alternations require; yet the correct apportionment of action and reaction is, for us, of greatest importance. In this regard, moreover, there is always the empty problem as to whether two things may stand in causal relation,-- empty, because the answer is always yes. The scientific and practical problem is as to whether there exists an actual causal nexus. The same relation occurs in the problem of reciprocal influences. No one will say, for example, that any event exercises a reciprocal influence on the sun, but apart from such relatively few cases it would not only be supposed that A is the cause of the effect B, but also that B might have reciprocally influenced A. Regard for this possibility may save one from many mistakes.

One important source of error with regard to cause and effect lies in the general and profound supposition that the cause must have a certain similarity to the effect. So Ovid, according to J. S. Mill, has Medea brew a broth of long-lived animals; and popular superst.i.tions are full of such doctrine. The lung of a long-winded fox is used as a cure for asthma, the yarrow is used to cure jaundice, agaricos is used for blisters, aristolochia (the fruit of which has the form of a uterus) is used for the pains of child-birth, and nettle-tea for nettle-rash. This series may be voluntarily increased when related to the holy patron saints of the Catholic Church, who are chosen as protectors against some especial condition or some specific difficulty because they at one time had some connection with that particular matter. So the holy Odilia is the patron saint for diseases of the eye, not because she knew how to cure the eyes, but because her eyes were put out with needles. The thief Dismas is the patron of the dying because we know nothing about him save that he died with Christ. St. Barbara, who is pictured together with a tower in which she was imprisoned, and which was supposed to be a powder house, has become the patron saint of artillery. In the same manner St. Nicholas is, according to Simrock, the patron of sailors because his name resembles Nichus, Nicor, Nicker, which is the name of the unforgotten old German sea-deity.

Against such combinations, external and unjustified, not even the most educated and skilful is safe. n.o.body will doubt that he is required to make considerable effort in his causal interpretation because of the sub-conscious influence of such similarities. The matter would not be so dangerous, all in all, because such mistakes may be easily corrected and the attention of people may be called

to the inadequacy of such causation--but the reason for this kind of correlations is rarely discovered. Either people do not want to tell it because they instinctively perceive that their causal interpretation cannot be justified, or they cannot even express it because the causal relation had been a.s.sumed only subconsciously, and they are hence unaware of the reasons for it and all the more convinced that they are right. So for example, an intelligent man told me that he suspected another of a murder because the latter's mother died a violent death. The witness stuck to his statement: "the man who had once had something to do with killing must have had something to do with this killing." In a similar manner, a whole village accused a man of arson because he was born on the night on which a neighboring village burned down. Here, however, there was no additional argument in the belief that his mother had absorbed the influence of the fire inasmuch as the latter was told that there had been a fire only after the child was born. "He once had something to do with fire," was the basis of the judgment, also in this case.

There are innumerable similar examples which, with a large number of habitual superst.i.tious presuppositions, make only false causality. Pearls mean tears because they have similar form; inasmuch as the cuckoo may not without a purpose have only two calls at one time and ten or twenty at another, the calls must mean the number of years before death, before marriage, or of a certain amount of money, or any other countable thing. Such notions are so firmly rooted in the peasantry and in all of us, that they come to the surface, whether consciously or unconsciously, and influence us more than we are accustomed to suppose they do. Whenever anybody a.s.sures us that he is able to a.s.sert absolutely, though not altogether prove a thing, this a.s.surance may be variously grounded, but not rarely it is no more than one of these false correlations. Schopenhauer has said, that "motivation is causality seen from within,"--and one may add conversely that causality is motivation seen from without. What is a.s.serted must be motivated, and that is done by means of causality--if no real ultimate cause is found a false, superficial and insufficient one is adopted, inasmuch as we ever strive to relate things causally, in the knowledge that, otherwise, the world would be topsy-turvy. "Everywhere," says Stricker, "we learn that men who do not a.s.sociate their experiences according to right cause are badly adapted to their environment; the pictures of artists are disliked, the laborer's

work does not succeed; the tradesman loses his money, and the general his battle. And we may add, "The criminalist his case." For whoever seeks the reason for a lost case certainly will find it in the ignorance of the real fact and in the incorrect cordination of cause and effect. The most difficult thing in such cordination is not that it has to be tested according to the notion one has for himself of the chain of events; the difficulty lies in the fact that the point of view and mental habits of the man who is suspected of the effects must be adopted. Without this the causal relations as they are arrived at by the other can never be reached, or different results most likely ensue.

The frequency of mistakes like those just mentioned is well known. They affect history. Even La Rochefoucauld was of the opinion that the great and splendid deeds which are presented by statesmen as the outcome of far-reaching plans are, as a rule, merely the result of inclination and pa.s.sion. This opinion concerns the lawyer's task also, for the lawyer is almost always trying to discover the moving, great, and unified plan of each crime, and in order to sustain such a notion, prefers to perfect a large and difficult theoretic construction, rather than to suppose that there never was a plan, but that the whole crime sprang from accident, inclination, and sudden impulse. The easiest victims in this respect are the most logical and systematic lawyers; they merely presuppose, "I would not have done this" and forget that the criminal was not at all so logical and systematic, that he did not even work according to plan, but simply followed straying impulses.

Moreover, a man may have determined his causal connections correctly, yet have omitted many things, or finally have made a voluntary stop at some point in his work, or may have carried the causal chain unnecessarily far. This possibility has been made especially clear by J. S. Mill, who showed that the immediately preceding condition is never taken as cause. When we throw a stone into the water we call the cause of its sinking its gravity, and not the fact that it has been thrown into the water. So again, when a man falls down stairs and breaks his foot, in the story of the fall the law of gravity is not mentioned; it is taken for granted. When the matter is not so clear as in the preceding examples, such facts are often the cause of important misunderstandings. In the first case, where the immediately preceding condition is *not mentioned, it is the inaccuracy of the expression that is at fault, for we see that at least in scientific form, the efficient cause is always the immedi-

ately preceding condition. So the physician says, "The cause of death was congestion of the brain in consequence of pressure resulting from extravasation of the blood." And he indicates only in the second line that the latter event resulted from a blow on the head. In a similar manner the physicist says that the board was sprung as a consequence of the uneven tension of the fibers; he adds only later that this resulted from the warmth, which again is the consequence of the direct sunlight that fell on the board. Now the layman had in both cases omitted the proximate causes and would have said in case 1, "The man died because he was beaten on the head," and in case 2 "The board was sprung because it lay in the sun." We have, therefore, to agree to the surprising fact that the layman skips more intermediaries than the professional, but only because either he is ignorant of or ignores the intervening conditions. Hence, he is also in greater danger of making a mistake through omission.

Inasmuch as the question deals only with the scarcity of correct knowledge of proximate causes, we shall set aside the fact that lawyers themselves make such mistakes, which may be avoided only by careful self-training and cautious attention to one's own thoughts. But we have at the same time to recognize how important the matter is when we receive long series of inferences from witnesses who give expression only to the first and the last deduction. If we do not then examine and investigate the intermediary links and their justification, we deserve to hear extravagant things, and what is worse, to make them, as we do, the foundation of further inference. And once this is done no man can discover where the mistake lies.

If again an inference is omitted as self-evident (cf. the case of gravity, in falling down stairs) the source of error and the difficulty lies in the fact that, on the one hand, not everything is as self-evident as it seems; on the other, that two people rarely understand the same thing by "self-evident," so that what is self-evident to one is far from so to the other. This difference becomes especially clear when a lawyer examines professional people who can imagine offhand what is in no sense self-evident to persons in other walks of life. I might cite out of my own experience, that the physicist Boltzmann, one of the foremost of living mathematicians, was told once upon a time that his demonstrations were not sufficiently detailed to be intelligible to his cla.s.s of non-professionals, so that his hearers could not follow him. As a result, he carefully counted the simplest additions or interpolations on the blackboard, but at

the same time integrated them, etc., in his head, a thing which very few people on earth can do. It was simply an off-hand matter for this genius to do that which ungenial mortals can not.

This appears in a small way in every second criminal case. We have only to subst.i.tute the professionals who appear as witnesses. Suppose, e. g., that a hunter is giving testimony. He will omit to state a group of correlations; with regard to things which are involved in his trade, he will reach his conclusion with a single jump. Then we reach the fatal circle that the witness supposes that we can follow him and his deductions, and are able to call his attention to any significant error, while we, on the other hand, depend on his professional knowledge, and agree to his leaping inferences and allow his conclusions to pa.s.s as valid without knowing or being able to test them.

The notion of "specialist" or "professional" must be applied in such instances not only to especial proficients in some particular trade, but also to such people as have by accident merely, any form of specialized knowledge, e. g., knowledge of the place in which some case had occurred. People with such knowledge present many a thing as self-evident that can not be so to people who do not possess the knowledge. Hence, peasants who are asked about some road in their own well known country reply that it is "straight ahead and impossible to miss" even when the road may turn ten times, right and left.

Human estimates are reliable only when tested and reviewed at each instant; complicated deductions are so only when deduction after deduction has been tested, each in itself, Lawyers must, therefore, inevitably follow the rule of requiring explication of each step in an inference--such a requirement will at least narrow the limits of error.

The task would be much easier if we were fortunate enough to be able to help ourselves with experiments. As Bernard[1] says, "There is an absolute determinism in the existential conditions of natural phenomena, as much in living as in non-living bodies. If the condition of any phenomenon is recognized and fulfilled the phenomenon must occur whenever the experimenter desires it." But such determination can be made by lawyers in rare cases only, and to-day the criminalist who can test experimentally the generally a.s.serted circ.u.mstance attested by witnesses, accused, or experts, [1] C. Bernard: Introduction cine Experimentale. Paris 1871.

is a rarissima avis. In most cases we have to depend on our experience, which frequently leaves us in difficulties if we fail thoroughly to test it. Even the general law of causation, that every effect has its cause, is formulated, as Hume points out, only as a matter of habit. Hume's important discovery that we do not observe causality in the external world, demonstrates only the difficulty of the interpretation of causality. The weakness of his doctrine lies in his a.s.sertion that the knowledge of causality may be obtained through habit because we perceive the connection of similars, and the understanding, through habit, deduces the appearance of the one from that of the other. These a.s.sertions of the great thinker are certainly correct, but he did not know how to ground them. Hume teaches the following doctrine: The proposition that causes and effects are recognized, not by the understanding but because of experience, will be readily granted if we think of such things as we may recollect we were once altogether unacquainted with. Suppose we give a man who has no knowledge of physics two smooth marble plates. He will never discover that when laid one upon the other they are hard to separate. Here it is easily observed that such properties can be discovered only through experience. n.o.body, again, has the desire to deceive himself into believing that the force of burning powder or the attraction of a magnet could have been discovered a priori. But this truth does not seem to have the same validity with regard to such processes as we observed almost since breath began. With regard to them, it is supposed that the understanding, by its own activity, without the help of experience can discover causal connections. It is supposed that anybody who is suddenly sent into the world will be able at once to deduce that a billiard ball will pa.s.s its motion on to another by a push.

But that this is impossible to derive a priori is shown through the fact that elasticity is not an externally recognizable quality, so that we may indeed say that perhaps no effect can be recognized unless it is experienced at least once. It can not be deduced a priori that contact with water makes one wet, or that an object responds to gravity when held in the hand, or that it is painful to keep a finger in the fire. These facts have first to be experienced either by ourselves or some other person. Every cause, Hume argues therefore, is different from its effect and hence can not be found in the latter, and every discovery or representation of it a priori must remain voluntary. All that the understanding can do is to simplify

the fundamental causes of natural phenomena and to deduce the individual effects from a few general sources, and that, indeed, only with the aid of a.n.a.logy, experience, and observation.

But then, what is meant by trusting the inference of another person, and what in the other person's narrative is free from inference? Such trust means, to be convinced that the other has made the correct a.n.a.logy, has made the right use of experience, and has observed events without prejudice. That is a great deal to presuppose, and whoever takes the trouble of examining however simple and short a statement of a witness with regard to a.n.a.logy, experience, and observation, must finally perceive with fear how blindly the witness has been trusted. Whoever believes in knowledge a priori will have an easy job: "The man has perceived it with his mind and reproduced it therewith; no objection may be raised to the soundness of his understanding; ergo, everything may be relied upon just as he has testified to it." But he who believes in the more uncomfortable, but at least more conscientious, skeptical doctrine, has, at the minimum, some fair reason for believing himself able to trust the intelligence of a witness. Yet he neither is spared the task of testing the correctness of the witness's a.n.a.logy, experience and observation.

Apriorism and skepticism define the great difference in the att.i.tude toward the witness. Both skeptic and apriorist have to test the desire of the witness to lie, but only the skeptic needs to test the witness's ability to tell the truth and his possession of sufficient understanding to reproduce correctly; to examine closely his innumerable inferences from a.n.a.logy, experience and observation. That only the skeptic can be right everybody knows who has at all noticed how various people differ in regard to a.n.a.logies, how very different the experiences of a single man are, both in their observation and interpretation. To distinguish these differences clearly is the main task of our investigation.

There are two conditions to consider. One is the strict difference between what is causally related and its accidental concomitants,-- a difference with regard to which experience is so often misleading, for two phenomena may occur together at the same time without being causally connected. When a man is ninety years old and has observed, every week in his life, that in his part of the country there is invariably a rainfall every Tuesday, this observation is richly and often tested, yet n.o.body will get the notion of causally connecting Tuesday and rain--but only because such connection would

be regarded as generally foolish. If the thing, however, may be attributed to coincidence with a little more difficulty, then it becomes easier to suppose a causal connection; e. g., as when it rains on All- souls day, or at the new moon. If the accidental nature of the connection is still less obvious, the observation becomes a much- trusted and energetically defended meteorological law. This happens in all possible fields, and not only our witnesses but we ourselves often find it very difficult to distinguish between causation and accident. The only useful rule to follow is to presuppose accident wherever it is not indubitably and from the first excluded, and carefully to examine the problem for whatever causal connection it may possibly reveal. "Whatever is united in any perception must be united according to a general rule, but a great deal more may be present without having any causal relation."

The second important condition was mentioned by Schopenhauer:[1] "As soon as we have a.s.signed causal force to any great influence and thereby recognized that it is efficacious, then its intensification in the face of any resistance according to the intensity of the resistance will produce finally the appropriate effect. Whoever cannot be bribed by ten dollars, but vacillates, will be bribed by twenty-five or fifty."

This simple example may be generalized into a golden rule for lawyers and requires them to test the effect of any force on the accused at an earlier time in the latter's life or in other cases,-- i. e., the early life of the latter can never be studied with sufficient care. This study is of especial importance when the question is one of determining the culpability of the accused with regard to a certain crime. We have then to ask whether he had the motive in question, or whether the crime could have been of interest to him. In this investigation the problem of the necessary intensity of the influence in question need not, for the time, be considered; only its presence needs to be determined. That it may have disappeared without any demonstrable special reason is not supposable, for inclinations, qualities, and pa.s.sions are rarely lost; they need not become obvious so long as opportunity and stimulus are absent, and they may be in some degree suppressed, but they manifest themselves as soon as--Schopenhauer's twenty-five or fifty dollars appear. The problem is most difficult when it requires the conversion of certain related properties, e. g., when the problem is one of suspecting a person of murderous inclination, and all that [1] Schopenhauer: Die beiden Grundprobleme der Ethik.

can be shown in his past life is the maltreatment of animals. Or again, when cruelty has to be shown and all that is established is great sensuality. Or when there is no doubt about cruelty and the problem is one of supposing intense avarice. These questions of conversion are not especially difficult, but when it must be explained to what such qualities as very exquisite egoism, declared envy, abnormal desire for honor, exaggerated conceit, and great idleness may lead to, the problem requires great caution and intensive study.

Section 25. (c) Skepticism.

Hume's skepticism is directly connected with the subject of the preceding chapter, but wants still a few words for itself. Though it is not the lawyer's problem to take an att.i.tude with regard to philosophical skepticism, his work becomes essentially easier through the study of Hume's doctrines.

According to these, all we know and infer, in so far as it is unmathematical, results from experience, and our conviction of it and our reasoning about it, means by which we pa.s.s the bounds of sense-perception, depend on sensation, memory and inference from causation. Our knowledge of the relation of cause and effect results also from experience, and the doctrine, applied to the work of the criminalist, may be formulated as follows: "Whatever we take as true is not an intellectual deduction, but an empirical proposition." In other words, our presuppositions and inferential knowledge depend only upon those innumerable repet.i.tions of events from which we postulate that the event recurred in the place in question. This sets us the problem of determining whether the similar cases with which we compare the present one really are similar and if they are known in sufficiently large numbers to exclude everything else.

Consider a simple example. Suppose somebody who had traveled all through Europe, but had never seen or heard of a negro, thought about the pigmentation of human beings: neither all his thinking nor the a.s.sistance of all possible scientific means can lead him to the conclusion that there are also black people--that fact he can only discover, not think out. If he depends only on experience, he must conclude from the millions of examples he has observed that all human beings are white. His mistake consists in the fact that the immense number of people he has seen belong to the inhabitants of a single zone, and that he has *failed to observe the inhabitants of other regions.

In our own cases we need no examples, for I know of no inference which was not made in the following fashion: "The situation was so in a hundred cases, it must be so in this case." We rarely ask whether we know enough examples, whether they were the correct ones, and whether they were exhaustive. It will be no mistake to a.s.sert that we lawyers do this more or less consciously on the supposition that we have an immense collection of suggestive a priori inferences which the human understanding has brought together for thousands of years, and hence believe them to be indubitably certain. If we recognize that all these presuppositions are compounds of experience, and that every experience may finally show itself to be deceptive and false; if we recognize how the actual progress of human knowledge consists in the addition of one hundred new experiences to a thousand old ones, and if we recognize that many of the new ones contradict the old ones: if we recognize the consequence that there is no reason for the mathematical deduction from the first to the hundred-and-first case, we shall make fewer mistakes and do less harm. In this regard, Hume[1] is very illuminative.

According to Masaryk,[2] the fundamental doctrine of Humian skepticism is as follows: "If I have had one and the same experience ever so often, i. e., if I have seen the sun go up 100 times, I expect to see it go up the 101st time the next day, but I have no guarantee, no certainty, no evidence for this belief. Experience looks only to the past, not to the future. How can I then discover the 101st sunrise in the first 100 sunrises? Experience reveals in me the habit to expect similar effects from similar circ.u.mstances, but the intellect has no share in this expectation."

All the sciences based on experience are uncertain and without logical foundation, even though their results, as a whole and in the ma.s.s, are predictable. Only mathematics offers certainty and evidence. Therefore, according to Hume, sciences based on experience are unsafe because the recognition of causal connection depends on the facts of experience and we can attain to certain knowledge of the facts of experience only on the ground of the evident relation of cause and effect.

This view was first opposed by Reid, who tried to demonstrate that we have a clear notion of necessary connection. He grants that this notion is not directly attained either from external or internal experience, but a.s.serts its clearness and certainty in spite [1] Cf. Hume's Treatise of Human Nature.

[2] Masaryk: David Hume's Skepsis. Vienna 1884.

of that fact. Our mind has the power to make its own concepts and one such concept is that of necessary connection. Kant goes further and says that Hume failed to recognize the full consequences of his own a.n.a.lysis, for the notion of causality is not the only one which the understanding uses to represent a priori the connection of objects. And hence, Kant defines psychologically and logically a whole system of similar concepts. His "Critique of Pure Reason" is intended historically and logically as the refutation of Hume's skepticism. It aims to show that not only metaphysics and natural science have for their basis "synthetic judgments a priori," but that mathematics also rests on the same foundation.

*** You are reading on ***

Be that as it may, our task is to discover the application of Hume's skepticism to our own problems in some clear example. Let us suppose that there are a dozen instances of people who grew to be from 120 to 140 years old. These instances occur among countless millions of cases in which such an age was not reached. If this small proportion is recognized, it justifies the postulate that n.o.body on earth may attain to 150 years. But now it is known that the Englishman Thomas Parr got to be 152 years old, and his countryman Jenkins was shown, according to the indubitable proofs of the Royal Society, to be 157 years old at least (according to his portrait in a copper etching he was 169 years old). Yet as this is the most that has been scientifically proved I am justified in saying that n.o.body can grow to be 200 years old. Nevertheless because there are people who have attained the age of 180 to 190 years, n.o.body would care to a.s.sert that it is absolutely impossible to grow so old. The names and histories of these people are recorded and their existence removes the great reason against this possibility.

It is of exceeding importance to establish such purely empiric laws in our science, which has done little with such matters because, owing to scanty research into most of them, we need these laws. We know approximately that this and that have come to light so and so often, but we have not reduced to order and studied systematically the cases before us, and we dare not call this knowledge natural law because we have subjected it to no inductive procedure. "The reference of any fact discovered by experience to general laws or rules we call induction. It embraces both observation and deduction." Again, it may be defined as "the generalization or universalization of our experiences; and inference that a phenomenon occurring x times will invariably occur when the essential circ.u.mstances remain identical. The earliest investigators started with the simplest inductions,--that fire burns, that water flows downward,--so that new, simple truths were continually discovered. This is the type of scientific induction and it requires further, the addition of certainty and accuracy."[1]

The foregoing might have been written expressly for us lawyers, but we have to bear in mind that we have not proceeded in our own generalizations beyond "fire burns, water flows downward." And such propositions we have only derived from other disciplines. Those derived from our own are very few indeed, and to get more we have very far to go. Moreover, the laws of experience are in no way so certain as they are supposed to be, even when mathematically conceived. The empirical law is established that the sum of the three angles of a triangle is equal to two right angles. And yet n.o.body, ever since the science of surveying has been invented, has succeeded in discovering 180 degrees in any triangle. Now then, when even such things, supposed ever since our youth to be valid, are not at all true, or true theoretically only, how much more careful must we be in making inferences from much less certain rules, even though we have succeeded in using them before in many a.n.a.logous cases? The activity of a criminalist is of far too short duration to permit him to experience any more than a very small portion of the possibilities of life, and suggestions from foreign sources are very [1] ttingen: Die Moralstatistik. Erlangen 1882.

rare. The situation is different in other disciplines. "Our experience," says James Sully,"[1] enables us to express a number of additional convictions. We can predict political changes and scientific developments, and can conceive of the geographical conditions at the north pole." Other disciplines are justified to a.s.sert such additional propositions, but is ours? A man may have dealt for years with thieves and swindlers, but is he justified in deducing from the inductions made in his experience, the situation of the first murderer he deals with? Is he right in translating things learned by dealing with educated people to cases where only peasants appear? In all these cases what is needed in making deductions is great caution and continual reminder to be very careful, for our work here still lacks the proper material. In addition we have to bear in mind that induction is intimately related to a.n.a.logy. According to Lipps[2] the ground of one is the ground of the other; they both rest on the same foundation. "If I am still in doubt whether the fact on which a moment ago I depended as the sufficient condition for a judgment may still be so regarded, the induction is uncertain. It is unjustified when I take for sufficiently valid something that as a matter of fact ought not to be so taken." If we bear in mind how much we are warned against the use of a.n.a.logy, how it is expressly excluded in the application of certain criminal laws, and how dangerous the use of every a.n.a.logy is, we must be convinced that the use for our cases of both induction and a.n.a.logy, is always menace. We have at the same time to bear in mind how much use we actually make of both; even our general rules--e. g., concerning false testimony,--bias, reversibility, special inclinations, etc.-- and our doctrines concerning the composition and indirection of testimony, even our rules concerning the value of witnesses and confessions, all these depend upon induction and a.n.a.logy. We pa.s.s by their use in every trial from case to case. A means so frequently and universally used must, however, be altogether reliable, or be handled with the greatest care. As it is not the first it must be handled in the second way.

We have yet to indicate the various ways in which induction may be used. Fick has already called attention to the astounding question concluding Mill's system of logic: Why, in many cases, is a single example sufficient to complete induction, while in other <139> cases myriads of unanimous instances admitting of no single known or suspected exception, make only a small step toward the establishment of a generally valid judgment?

[1] James Sully: "Die Illusionen" in Vol. 62 of the Internation. Wissensohft Bibliothek. Leipzig 1884.

[2] Th. Lipps: Grundtatssehen des Seelenlebens. Bonn 1883.

This question is of enormous significance in criminal cases because it is not easy to determine in any particular trial whether we have to deal with a situation of the first sort where a single example is evidential, or a situation of the second sort where a great many examples fail to be evidential. On this difficulty great mistakes depend, particularly mistakes of subst.i.tution of the first for the second. We are satisfied in such cases with a few examples and suppose ourselves to have proved the case although nothing whatever has been established.

We must see first of all if it is of any use to refer the difficulty of the matter to the form in which the question is put, and to say: The difficulty results from the question itself. If it be asked, "Are any of the thousand marbles in the bag white marbles?" the question is determined by the first handful, if the latter brings to light a single white marble. If, however, the problem is phrased so: Does the bag contain white marbles *only? then, although 999 marbles might already have been drawn from the receptacle, it can not be determined that the last marble of the 1000 is white. In the same way, if people a.s.sert that the form of the question determines the answer, it does not follow that the form of the question is itself determined or distinguished inasmuch as the object belongs to the first or the second of the above named categories.

A safe method of distinction consists in calling the first form of the question positive and the second negative. The positive refers to a single unit; the negative to a boundless unit. If then I ask: Are there any white marbles whatever in the bag? the answer is rendered affirmative by the discovery of a single white marble. But if the question is phrased: Are there *only white marbles in the bag? merely its form is positive but its intent is negative. To conform the manner of the question to its intent, it would be necessary to ask: Are there no other colors than white among the marbles in the bag? And inasmuch as the negative under given circ.u.mstances is in many ways boundless, the question admits of no answer until the last marble has been brought to light. If the total number of marbles is unlimited the question can receive no complete inductive answer in mathematical form; it can be solved only approximately. So again, if one asks: Are there any purely blue birds? the answer is affirmative as soon as a single completely blue bird is brought to

light. But if the question is: Do not also striped birds exist? no answer is possible until the very last bird on earth is exhibited. In that way only could the possibility be excluded that not one of the terrestrial fowls is striped. As a matter of fact we are satisfied with a much less complete induction. So we say: Almost the whole earth has been covered by naturalists and not one of them reports having observed a striped bird; hence there would be none such even in the unexplored parts of the earth. This is an inductive inference and its justification is quite another question.

The above mentioned distinction may be made still clearer if instead of looking back to the form of the question, we study only the answer. We have then to say that positive statements are justified by the existence of a single instance, negative a.s.sertions only by the complete enumeration of all possible instances and never at all if the instances be boundless. That the negative proof always requires a series of demonstrations is well known; the one thing which may be firmly believed is the fact that the problem, whether a single example is sufficient, or a million are insufficient, is only a form of the problem of affirmative and negative a.s.sertions.

So then, if I ask: Has A ever stolen anything? it is enough to record one judgment against him, or to bring one witness on the matter in order to establish that A committed theft at least once in his life. If, however, it is to be proved that the man has never committed a theft, his whole life must be reviewed point by point, and it must be shown that at no instant of it did he commit larceny. In such cases we are content with much less. We say first of all: We will not inquire whether the man has never stolen. We will see merely whether he was never punished for theft. But here, too, we must beware and not commit ourselves to inquiring of all the authorities in the world, but only of a single authority, who, we a.s.sume, ought to know whether A was punished or not. If we go still further, we say that inasmuch as we have not heard from any authorities that the man was ever punished for stealing, we suppose that the man was never punished on that ground; and inasmuch as we have not examined anybody who had seen A steal, we preferably suppose that he has never stolen. This is what we call satisfactory evidence, and with the poor means at our disposal it must suffice.

In most cases we have to deal with mixed evidence, and frequently it has become habitual to change the problem to be solved according to our convenience, or at least to set aside some one thing. Sup-

pose that the issue deals with a discovered, well-retained footprint of a man. We then suspect somebody and compare the sole of his shoe with the impression. They fit in length and width, in the number of nails and in all the other possible indices, and we therefore a.s.sert: It is the footprint of the suspect, for "whose footprint?" is the problem we are troubling ourselves to solve. In truth we have only shown that the particular relations, in the matter of length, breadth, number of nails, etc., agree, and hence we regard the positive part of the evidence as sufficient and neglect the whole troublesome negative part, which might establish the fact that at the time and in the region in question, n.o.body was or could be whose foot could accurately fit that particular footprint. Therefore we have not proved but have only calculated the probability that at the time there might possibly not have been another person with a shoe of similar length, breadth and number of nails. The probability becomes naturally less as fewer details come to hand. The difficulty lies in finding where such probability, which stands for at least an a.s.sumption, must no longer be considered. Suppose, now, that neither shoe-nails nor patches, nor other clear clews can be proved and only length and width agree. If the agreement of the clews were really a substantiation of the proof by evidence, it would have to suffice as positive evidence; but as has been explained, the thing proved is not the point at issue, but another point.

The negative portion of the evidence will naturally be developed with less accuracy. The proof is limited to the a.s.sertion that such shoes as were indicated in the evidence were very rarely or never worn in that region, also that no native could have been present that the form of the nails allowed inference of somebody from foreign regions, one of which might be the home of the suspect, etc. Such an examination shows that what we call evidence is only probability or possibility.

Another form which seems to contradict the a.s.sertion that negative propositions are infinite is positive evidence in the shape of negation. If we give an expert a stain to examine and ask him whether it is a blood stain, and he tells us: "It is not a blood stain," then this single scientifically established a.s.sertion proves that we do not have to deal with blood, and hence "negative" proof seems brought in a single instance. But as a matter of fact we deal here with an actually positive proof, for the expert has given us the deduced proposition, not the essential a.s.sertion. He has found the

stain to be a rust stain or a tobacco stain, and hence he may a.s.sert and deduce that it is not blood. Even were he a skeptic, he would say, "We have not yet seen the blood of a mammal in which the characteristic signs for recognition were not present, and we have never yet recognized a body without the blood pertaining to it, and hence we may say, we are not dealing with blood because all of us found the characteristics of the stain to be what we have been until now accustomed to call the characteristics of rust stain."

We have still to touch upon the difference between logical connection and experience. If I say, "This mineral tastes salty, therefore it is soluble in water," the inference depends upon logical relationships, for my intent is: "If I perceive a salty taste, it has to be brought to the nerves of taste, which can be done only by the combination of the mineral with the saliva, hence by its solution in the saliva. But if it is soluble in saliva it must also be soluble in water." If I say on the other hand, "This mineral tastes salty, has a hardness of 2, a specific gravity of 2.2, and consequently it crystallizes hexagonally,"--this statement depends on experience, for what I really say is: "I know first of all, that a mineral which has the qualities mentioned must be rock salt; for at the least, we know of no mineral which has these qualities and is not rock salt, and which in the second place crystallizes hexagonally as rock salt does,--a way which, at least, we find rock salt never to have missed." If we examine the matter still more closely we become convinced that in the first case only the formal and logical side, in the second the experiential aspect predominates. The premises of both cases are purely matters of experience and the formal question of inference is a matter of logic. Only,--at one time the first question, at another the second comes more obviously into the foreground. Although this matter appears self-evident it is not indifferent. It is well known that whenever we are powerfully influenced by one thing, things of little intensity are either not experienced at all or only to a very small degree, and are therefore neglected. This is a fact which may indeed be shown mathematically, for infinity plus one equals infinity. When, therefore, we undergo great pain or great joy, any accompanying insignificant pain or any pleasure will be barely felt, just as the horses who drag a very heavy wagon will not notice whether the driver walking beside them adds his coat to the load (cf. Weber's law). Hence, when we criminalists study a difficult case with regard to the question of proof, there are two things to do in order to test the premises for correctness accord-

ing to the standards of our other experiences, and to draw logically correct inferences from these premises. If it happens that there are especial difficulties in one direction while by some chance those in the other are easily removed, it becomes surprising how often the latter are entirely ignored. And hence, the adjustment of inferences is naturally false even when the great difficulties of the first type are removed correctly. Therefore, if the establishment of a fact costs a good deal of pains and means the expenditure of much time, the business of logical connection appears so comparatively easy that it is made swiftly and--wrongly.

Mistakes become, at least according to my experience, still more frequent when the difficulty is logical and not empirical. As a matter of honesty, let me say that we criminalists are not trained logicians, however necessary it is that we shall be such, and most of us are satisfied with the barren remainder of what we learned long ago in the Gymnasium and have since forgotten. The difficulties which occur in the more important

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