criminal psychology-第42节
按键盘上方向键 ← 或 → 可快速上下翻页，按键盘上的 Enter 键可回到本书目录页，按键盘上方向键 ↑ 可回到本页顶部！
————未阅读完？加入书签已便下次继续阅读！
er； 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 nobody； 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 analogous 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 assert 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 analogy。 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 analogy； how it is expressly excluded in the application of certain criminal laws； and how dangerous the use of every analogy is； we must be convinced that the use for our cases of both induction and analogy； is always menace。 We have at the same time to bear in mind how much use we actually make of both； even our general rulese。 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 analogy。 We pass 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 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 substitution 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 assert 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 circumstances 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 assertions 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 assertions。
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 assume； 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 discove
