Part 10 (1/2)
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 astonis.h.i.+ng 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 relations.h.i.+p 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 relations.h.i.+p 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 r<o^>le 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] <o:>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.