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.
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.
We have to deal, then, only with greater or lesser possibilities and agree with the Humian idea that under similar conditions frequency of occurrence implies repet.i.tion in the next instance. Contrary evidence may be derived from several so-called phenomena of alternation. E. g., it is a well known fact that a number in the so-called Little Lottery, which has not been drawn for a long time, is sure finally to be drawn. If among 90 numbers the number 27 has not turned up for a long time its appearance becomes more probable with every successive drawing. All the so-called mathematical combinations of players depend on this experience, which, generalized, might be held to read: the oftener any event occurs (as the failure of the number 27 to be drawn) the less is the proba-
bility of its recurrence (i. e., it becomes more probable that 27 will be drawn)-and this seems the contrary of Hume"s proposition.
It may at first be said that the example ought to be put in a different form, i. e., as follows: If I know that a bag contains marbles, the color of which I do not know, and if I draw them one by one and always find the marble I have drawn to be white, the probability that the bag contains only white ones grows with every new drawing that brings a white marble to light. If the bag contains 100 marbles and 99 have been drawn out, n.o.body would suppose that the last one would be red-for the repet.i.tion of any event increases the probability of its occurrence.
This formulation proves nothing, inasmuch as a different example does not contradict the one it is intended to subst.i.tute. The explanation is rather as follows: In the first case there is involved the norm of equal possibilities, and if we apply the Humian principle of increase of probability through repet.i.tion, we find it effective in explaining the example. We have known until now always that the numbers in the Little Lottery are drawn equally, and with approximate regularity,-i. e., none of the single numbers is drawn for a disproportionately long time. And as this fact is invariable, we may suppose that every individual number would appear with comparative regularity. But this explanation is in accord with Hume"s doctrine.
The doctrine clarifies even astonishing statistical miracles. We know, e. g., that every year there come together in a certain region a large number of suicides, fractures of arms and legs, a.s.saults, unaddressed letters, etc. When, now, we discover that the number of suicides in a certain semester is significantly less than the number in the same semester of another year, we will postulate that in the next half-year a comparatively larger number of suicides will take place so that the number for the whole year will become approximately equal. Suppose we say: "There were in the months of January, February, March, April, May and June an average of x cases. Because we have observed the average to happen six times, we conclude that it will not happen in the other months but that instead, x+y cases will occur in those months, since otherwise the average annual count will not be attained." This would be a mistaken abstraction of the principle of equal distribution from the general Humian law, for the Humian law applied to this case indicates: "For a long series of years we have observed that in
this region there occur annually so and so many suicides; we conclude therefore that in this year also there will occur a similar number of suicides."
The principle of equal distribution presents itself therefore as a subordinate rule which must not be separated from the princ.i.p.al law. It is, indeed, valid for the simplest events. When I resolve to walk in x street, which I know well, and when I recall whether to-day is Sunday or a week day, what time it is and what the weather is like, I know quite accurately how the street will look with regard to the people that may be met there, although a large number of these people have chosen the time accidentally and might as well have pa.s.sed through another street. If, for once, there were more people in the street, I should immediately ask myself what unusual event had taken place.
One of my cousins who had a good deal of free time to dispose of, spent it for several months, with the a.s.sistance of his comrade, in counting the number of horses that pa.s.sed daily, in the course of two hours, by a caf they frequented. The conscientious and controlled count indicated that every day there came one bay horse to every four. If then, on any given day, an incommensurably large number of brown, black, and tawny horses came in the course of the first hour, the counters were forced to infer that in the next 60 minutes horses of a different color must come and that a greater number of bays must appear in order to restore the disturbed equilibrium. Such an inference is not contradictory to the Humian proposition. At the end of a series of examinations the counters were compelled to say, "Through so many days we have counted one bay to every four horses; we must therefore suppose that a similar relationship will be maintained the next day."So, the lawyer, too, must suppose, although we lawyers have nothing to do with figures, that he knows nothing a priori, and must construct his inferences entirely from experience. And hence we must agree that our premises for such inferences are uncertain, and often subject to revision, and often likely, in their application to new facts, to lead to serious mistakes, particularly if the number of experiences from which the next moment is deduced, are too few; or if an unknown, but very important condition is omitted.
These facts must carefully be kept in mind with reference to the testimony of experts. Without showing ourselves suspicious, or desirous of confusing the professional in his own work, we must consider that the progress of knowledge consists in the collection
of instances, and anything that might have been normal in 100 cases, need not in any sense be so when 1000 cases are in question. Yesterday the norm may have been subject to no exception; to-day exceptions are noted; and to-morrow the exception has become the rule.
Hence, rules which have no exceptions grow progressively rarer, and wherever a single exception is discovered the rule can no longer be held as normative. Thus, before New Holland was discovered, all swans were supposed to be white, all mammals incapable of laying eggs; now we know that there are black swans and that the duck-bill lays eggs. Who would have dared to a.s.sert before the discovery of the X-ray that light can penetrate wood, and who, especially, has dared to make generalizations with regard to the great inventions of our time which were not afterwards contradicted by the facts? It may be that the time is not too far away in which great, tenable and unexceptionable principles may be posited, but the present tendency is to beware of generalizations, even so far as to regard it a sign of scientific insight when the composition of generally valid propositions is made with great caution. In this regard the great physicians of our time are excellent examples. They hold: "whether the phenomenon A is caused by B we do not know, but n.o.body has ever yet seen a case of A in which the precedence of B could not be demonstrated." Our experts should take the same att.i.tude in most cases. It might be more uncomfortable for us, but certainly will be safer; for if they do not take that att.i.tude we are in duty bound to presuppose in our conclusions that they have taken it. Only in this wise, by protecting ourselves against apparently exceptionless general rules, can our work be safely carried on.
This becomes especially our duty where, believing ourselves to have discovered some generally valid rule, we are compelled to draw conclusions without the a.s.sistance of experts. How often have we depended upon our understanding and our "correct" a priori method of inference, where that was only experience,-and such poor experience! We lawyers have not yet brought our science so far as to be able to make use of the experience of our comrades with material they have reviewed and defined in writing. We have bothered a great deal about the exposition of some legal difficulty, the definition of some judicial concept, but we have received little instruction or tradition concerning mankind and its pa.s.sions. Hence, each one has to depend on his own experience, and that is supposed
to be considerable if it has a score of years to its back, and is somewhat supplemented by the experience, of others. In this regard there are no indubitable rules; everybody must tell himself, "I have perhaps never experienced this fact, but it may be that a thousand other people have seen it, and seen it in a thousand different ways. How then, and whence, my right to exclude every exception?"
We must never forget that every rule is shattered whenever any single element of the situation is unknown, and that happens very easily and frequently. Suppose that I did not have full knowledge of the nature of water, and walked on terra firma to the edge of some quiet, calm pool. When now I presume: water has a body, it has a definite density, it has consistency, weight, etc., I will also presume that I may go on walking over its surface just as over the surface of the earth,-and that, simply because I am ignorant of its fluidity and its specific gravity. Liebman[1] summarizes the situation as follows. The causal nexus, the existential and objective relation between lightning and thunder, the firing of powder and the explosion, are altogether different from the logical nexus, i. e. the mere conceptual connection between antecedent and consequent in deduction. This const.i.tutes the well known kernel of Humian skepticism. We must keep in mind clearly that we never can know with certainty whether we are in possession of all the determining factors of a phenomenon, and hence we must adhere to the only unexceptionable rule: Be careful about making rules that admit of no exceptions. There is still another objection to discuss, i. e. the mathematical exception to Humian skepticism. It might be held that inasmuch as the science of justice is closely related in many ways to mathematics, it may permit of propositions a priori. Leibnitz already had said, "The mathematicians count with numbers, the lawyers with ideas,-fundamentally both do the same thing." If the relationship were really so close, general skepticism about phenomenal sciences could not be applied to the legal disciplines. But we nowadays deal not with concepts merely, and in spite of all obstruction, Leibnitz"s time has pa.s.sed and the realities of our profession, indeed its most important object, the human being itself, const.i.tute an integrating part of our studies. And the question may be still further raised whether mathematics is really so exempt from skepticism. The work of Gauss, Lobatschewski, Bolyai, Lambert, would make the answer negative.
[1] Liebman Zur a.n.a.lysis der Wirklichkeit. Stra.s.sburg 1888.
Let us, for once, consider what significance mathematical postulates have. When Pythagoras discovered his proposition in such a way that he first drew a right-angled triangle and then built a square on each of the sides, and finally measured the area of each and compared them, he must at first have got the notion that that also might be merely accidental. If he had made the construction 10 or 100 times with various triangles and these had resulted always identically, only then might he have been justified in saying that he had apparently discovered a theorem. But then his process was just as thoroughly experiential as that of a scientist who says that a bird has never yet been observed to give birth to living young, and that hence all birds lay eggs.
But Pythagoras did not proceed in this experiential manner in the discovery of his theorem. He constructed and he counted, and when he did that he acted on postulates: "If this is a right-angled triangle and if that be a square, so,"-and this is just what is done in every science. The general propositions are, "If the relations remain the same as formerly the moon must rise to-morrow at such and such a time." "If this step in a deduction is not false, if it is well grounded at this point, if it really refers to x, it follows.... " In his procedures the criminalist does exactly the same thing. What he must be skeptical about is the postulates from which he starts.
Section 26. (d) The Empirical Method in the Study of Cases.
Properly to bound our discussion of Humian skepticism, a few words have to be said concerning the empirical method of the sciences. We will call those laws purely empirical which, in the study of nature, yield regularities that are demonstrated by observation and experiment, but upon which little or no reliance is placed with regard to cases which differ considerably from the observed. The latter is done because no reason is seen for the existence of such laws. The empirical rule is, therefore, no final law, but is capable of explaining, especially when true, e. g., the succession of a certain condition of weather from certain meteorological signs, the improvement of species through crossing, the fact that some alloys are harder than their components, and so on. Or, to choose examples from our own field, jurisprudence may a.s.sert as empirical law that a murderer is a criminal who has gone unpunished for his earlier crimes; that all gamblers show such significant resemblances; that the criminal who has soiled his hands with blood in some violent
crime was accustomed to wipe them on the underside of a table; that the slyest person generally perpetrates some gross stupidity after committing a serious crime, and so renders discovery simpler; that l.u.s.t and cruelty have a certain relation; that superst.i.tion plays a great rle in crime, etc.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 logical tasks are intelligible when compared with the lesser difficulties; and when one of these larger problems is by good fortune rightly solved, the effort and the work required by the solution make it easy to forget asking whether the premises are correct; they are a.s.sumed as self-evident. Hence, in the review of the basis for judgment, it is often discovered that the logical task has been performed with care, with the expenditure of much time, etc., only to be based upon some apparently unessential presupposition which contradicts all experience and is hence materially incorrect. Consequence,-the inference is wrong since the premise was wrong, and the whole work has gone for nothing. Such occurrences convince one that no judge would have been guilty of them if the few difficulties concerning the fact in question were not, because treated in the light of the effort required by the logical work, quite neglected. Nor does this occur unconsciously, or as a consequence of a sort of lapse of memory concerning the meaning or the importance of an empirical problem, it also happens at least half consciously by way of a characteristic psychic process which everybody may identify in his own experience: i. e., the idea occurs, in some degree subconsciously, that the overgreatness of the work done in one direction ought to be corrected by the inadequacy of the work done in the other direction. And this happens in lawyer"s work often, and being frequently justifiable, becomes habitual. If I, for example, have examined ten unanimous witnesses concerning the same event and have completely demonstrated
the status of the case, I ought, in examining the last two witnesses, who are perhaps no longer needed but have been summoned and appear, certainly to proceed in a rapid manner. This justifiable neglect is then half unconsciously transferred to other procedures where there is possible no equalization of the hypertrophy of work in one direction with the dwarfing of it in another, and where the mistake causes the result to be wrong. However I may have been bothered by the multiplication of ten groups of factors and whatever accuracy I may have applied to a task can not permit me to relax my attention in the addition of the individual results. If I do I am likely to commit an error and the error renders all the previous labor worthless.
Indeed, it may be a.s.serted that all logic is futile where the premises or a single premise may be wrong. I expect, in truth, that the procedures here described will be doubted to be even possible, but doubters are recommended to examine a few cases for the presence of this sort of thing.
Section 27. (e) a.n.a.logy.
a.n.a.logy is the least negligible of all methods of induction because it rests at bottom on the postulate that one thing which has a number of qualities in common with another will agree with that other in one or more *additional qualities. In cases of a.n.a.logy, ident.i.ty is never a.s.serted; indeed, it is excluded, while a certain parallelism and agreement in specific points are a.s.sumed, i. e., introduced tacitly as a mutatis mutandis. Consider Lipps"s examples. He calls a.n.a.logy the transfer of judgment or the transition from similar to similar, and he adds that the value of such a process is very variable. If I have perceived x times that flowers of a certain color have perfume, I am inclined to expect perfume from flowers of the same color in x+1 cases. If I have observed x times that clouds of a certain structure are followed by rain I shall expect rain in the x+1st case. The first a.n.a.logy is worthless because there is no relation between color and perfume; the second is of great value because such a relation does exist between rain and clouds.
Simply stated, the difference between these two examples does not consist in the existence of a relationship in the one case and the absence of a relationship in the other; it consists in the fact that in the case of the flowers the relationship occurs now and then but is not permanently knowable. It is possible that there is a natural law controlling the relation between color and odor, and if
that law were known there would be no question of accident or of a.n.a.logy, but of law. Our ignorance of such a law, in spite of the multiplicity of instances, lies in the fact that we are concerned only with the converse relationships and not with the common cause of perfume and color. Suppose I see on the street a large number of people with winter over-coats and a large number of people with skates in their hands, I would hardly ask whether the coats are conditioned or brought out by the skates or the skates by the coats. If I do not conclude that the cold weather is the condition both of the need of over-coats and the utility of skates, I will suppose that there is some unintelligible reflexive relation between over-coats and skates. If I observe that on a certain day every week there regularly appear many well-dressed people and no workingmen on the street, if I am ignorant of the fact that Sunday is the cause of the appearance of the one and the disappearance of the other, I shall try in vain to find out how it happens that the working people are crowded out by the well-dressed ones or conversely.
The danger of a.n.a.logy lies in the fact that we prefer naturally to depend on something already known, and that the preference is the greater in proportion to our feeling of the strangeness and ominousness of the particular intellectual or natural regions in which we find ourselves. I have already once demonstrated[1] how disquieting it is to notice, during the examination of the jury, that the jurymen who ask questions try to find some relation to their own trades even though this requires great effort, and seek to bring the case they are asking about under the light of their particular profession. So, however irrelevant the statement of a witness may be, the merchant juryman will use it to explain Saldo-Conti, the carpenter juryman to explain carpentry, the agriculturist to notice the farming of cattle, and then having set the problem in his own field construct the most daring a.n.a.logies, for use in determining the guilt of the accused. And we lawyers are no better. The more difficult and newer a case is the more are we inclined to seek a.n.a.logies. We want supports, for we do not find firm natural laws, and in our fear we reach out after a.n.a.logies, not of course in law, because that is not permitted, but certainly in matters of fact. Witness X has given difficult testimony in a certain case. We seek an a.n.a.logy in witness Y of an older case, and we observe the present issue thus a.n.a.logically, without the least justification. We have never yet seen drops of blood on colored carpets, yet we believe in applying
our experience of blood stains on clothes and boots a.n.a.logically. We have before us a perfectly novel deed rising from perverted s.e.xual impulse-and we presuppose that the accused is to be treated altogether a.n.a.logously to another in a different case, although indeed the whole event was different.
[1] Manual for Examining Justices.
Moreover the procedure, where the a.n.a.logy is justified, is complex. "With insight," says Trendelenburg, "did the ancients regard a.n.a.logy as important. The power of a.n.a.logy lies in the construction and induction of a general term which binds the subconcept with regard to which a conclusion is desired, together with the individual object which is compared with the first, and which is to appear as a mediating concept but can not. This new general term is not, however, the highest concept among the three termini of the conclusion; it is the middle one and is nothing else than the terminus medius of the first figure." This clear statement shows not only how circ.u.mstantial every conclusion from a.n.a.logy is, but also how little it achieves. There is hardly any doubt of the well-known fact that science has much to thank a.n.a.logy for, since a.n.a.logy is the simplest and easiest means for progress in thought. If anything is established in any one direction but progress is desired in another, then the attempt is made to adapt what is known to the proximate unknown and to draw the possible inference by a.n.a.logy. Thousands upon thousands of a.n.a.logies have been attempted and have failed,- but no matter; one successful one became a hypothesis and finally an important natural law. In our work, however, the case is altogether different, for we are not concerned with the construction of hypotheses, we are concerned with the discovering of truth, or with the recognition that it cannot be discovered.
The only place where our problems permit of the use of a.n.a.logy is in the making of so-called constructions, i. e., when we aim to clarify or to begin the explanation of a case which is at present unintelligible, by making some a.s.sumption. The construction then proceeds in a.n.a.logy to some already well known earlier case. We say: "Suppose the case to have been so and so," and then we begin to test the a.s.sumption by applying it to the material before us, eliminating and constructing progressively until we get a consistent result. There is no doubt that success is frequently attained in this way and that it is often the only way in which a work may be begun. At the same time, it must be recognized how dangerous this is, for in the eagerness of the work it is easy to forget that so far, one is working only according to a.n.a.logy by means of an a.s.sumption
still to be proved. This a.s.sumption is in such cases suddenly considered as something already proved and is counted as such with the consequence that the result must be false. If you add the variability in value of a.n.a.logy, a variability not often immediately recognized, the case becomes still worse. We have never been on the moon, have therefore apparently no right to judge the conditions there-and still we know-only by way of a.n.a.logy- that if we jumped into the air there we should fall back to the ground. But still further: we conclude again, by a.n.a.logy, that there are intelligent beings on Mars; if, however, we were to say how these people might look, whether like us or like cubes or like threads, whether they are as large as bees or ten elephants, we should have to give up because we have not the slightest basis for a.n.a.logy.
In the last a.n.a.lysis, a.n.a.logy depends upon the recurrence of similar conditions. Therefore we tacitly a.s.sume when we judge by a.n.a.logy that the similarity of conditions contains an equivalence of ultimately valid circ.u.mstance. The certainty of a.n.a.logy is as great as the certainty of this postulate, and its right as great as the right of this postulate.