Criminal Psychology by Hans Gross (best book recommendations .TXT) 📕

whether we know enough examples, whether they were the correct ones, and whether they were exhaustive. It will be no mistake to assert 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 circumstances, 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 mass, 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 asserts its clearness and certainty in spite [1] Cf. Hume’s Treatise of Human Nature.

 

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

 

<p 131>

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 analysis, 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 nobody 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 nobody can grow to be 200 years old. Nevertheless because there are people who have attained the age of 180

to 190 years, nobody would care to assert 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 repetition 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-

<p 132>

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, nobody would suppose that the last one would be red—for the repetition 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 substitute. 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 repetition, 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, assaults, 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 <p 133>

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 principal 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 passed 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 assistance of his comrade, in counting the number of horses that passed daily, in the course of two hours, by a caf<e’> 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 <p 134>

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 assert 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,