er than I and conform to his opinion； there is as yet no suggestion。 And this pure form of change of opinion and of openness to conviction is commonest among us。 Whoever is able to correct the witness's apparently false conceptions and to lead him to discover his error of his own accord and then to speak the truth whoever can do this and yet does not go too far； deducing from the facts nothing that does not actually follow from themthat man is a master among us。
Section 2。 （b） The Method of Natural Science。＇1＇
If now we ask how we are to plan our work； what method we are to follow； we must agree that to establish scientifically the principles of our discipline alone is not sufficient。 If we are to make progress； the daily routine also must be scientifically administered。 Every sentence； every investigation； every official act must satisfy the same demand as that made of the entire juristic science。 In this way only
＇1＇ Cf。 H。 Gross's Archiv VI； 328 and VIII； 84。
can we rise above the mere workaday world of manual labor； with its sense…dulling disgust； its vexatious monotony； and its frightful menace against law and justice。 While jurists merely studied the language of dead laws； expounding them with effort unceasing； and； one may complain； propounding more； we must have despaired of ever being scientific。 And this because law as a science painfully sought justification in deduction from long obsolete norms and in the explanation of texts。 To jurisprudence was left only the empty shell； and a man like Ihering＇1＇ spoke of a ‘‘circus for dialectico… acrobatic tricks。''
Yet the scientific quality is right to hand。 We need only to take hold of the method； that for nearly a century has shown itself to us the most helpful。 Since Warnknig （1819）＇2＇ told us； ‘‘Jurisprudence must become a natural science；'' men have rung changes upon this battle cry （cf。 Spitzer＇3＇）。 And even if； because misunderstood； it led in some directions wrongly； it does seem as if a genuinely scientific direction might be given to our doctrines and their application。 We know very well that we may not hurry。 Wherever people delayed in establishing the right thing and then suddenly tried for it； they went in their haste too far。 This is apparent not only in the situations of life； it is visible； in the very recent hasty conclusions of the Lombrosists； in their very good； but inadequate observations； and unjustified and strained inferences。 We are not to figure the scientific method from these。＇4＇ It is for us to gather facts and to study them。 The drawing of inferences we may leave to our more fortunate successors。 But in the daily routine we may vary this procedure a little。 We draw there _*particular_ inferences from correct and simple observations。 ‘‘From facts to ideas；'' says ttingen。＇5＇ ‘‘The world has for several millenniums tried to subdue matter to preconceptions and the world has failed。 Now the procedure is reversed。'' ‘‘From facts to ideas''there lies our road； let us for once observe the facts of life without prejudice； without maxims built on preconceptions； let us establish them； strip them of all alien character。 Then finally； when we find nothing more in the least doubtful； we may theorize about them； and draw inferences； modestly and with caution。
Every fundamental investigation must first of all establish the
＇1＇ R。 v。 Ihering： Scherz und Ernst in der Jurisprudenz。 Leipzig 1885。
＇2＇ Warnkonig。 Versuch einer Begrndung des Rechtes。 Bonn 1819。
＇3＇ H。 Spitzer： ber das Verhltnis der Philosophie zu den organischen Naturwissensehaften。 Leipzig 1883。
＇4＇ Cf。 Gross's Archiv VIII 89。
＇5＇ A。 v。 ttingen： Moralstatistik。 Erlangen 1882。
nature of its subject matter。 This is the maxim of a book； ‘‘ber die Dummheit''＇1＇ （1886）； one of the wisest ever written。 The same axiomatic proposition must dominate every legal task； but especially every task of criminal law。 It is possible to read thousands upon thousands of testimonies and to make again this identical； fatiguing； contrary observation： The two； witness and judge； have not defined the nature of this subject； they have not determined what they wanted of each other。 The one spoke of one matter； the other of another； but just what the thing really was that was to have been established； the one did not know and the other did not tell him。 But the blame for this defective formulation does not rest with the witnessformulation was the other man's business。
When the real issue is defined the essentially modern and scientific investigation begins。 Ebbinghaus；＇2＇ I believe； has for our purpose defined it best。 It consists in trying to keep constant the complex of conditions demonstrated to be necessary for the realization of a given effect。 It consists in varying these conditions； in isolating one from the other in a numerically determinable order； and finally； in establishing the accompanying changes with regard to the effect； in a quantified or countable order。
I can not here say anything further to show that this is the sole correct method of establishing the necessary principles of our science。 The aim is only to test the practicality of this method in the routine of a criminal case； and to see if it is not； indeed； the only one by which to attain complete and indubitable results。 If it is； it must _*be of use_ not only during the whole trialnot only in the testing of collected evidence； but also in the testing of every individual portion thereof； analyzed into its component elements。
Let us first consider the whole trial。
The _*effect_ is here the evidence of A's guilt。 The complex conditions for its establishment are the collective instruments in getting evidence； the individual conditions are to be established by means of the individual sources of evidencetestimony of witnesses； examination of the premises； obduction； protocol； etc。
_The constantification of conditions_ now consists in standardizing the present instance； thus： Whenever similar circumstances are given； i。 e。： the same instruments of evidence are present； the evidence of guilt is established。 Now the accompanying changes with regard to the effect； i。 e。： proof of guilt through evidence； have to
＇1＇ Erdmann ber die Dummheit。 1886。
＇2＇ Ebbinghaus： ber das Gedchtniss。 Leipzig 1885。
be testedtherefore the individual conditionsi。e。： the individual sources of evidence have to be established and their values to be determined and _*varied_。 Finally； the accompanying change in effect （conviction by evidence） is to be tested。 The last procedure requires discussion； the rest is self evident。 In our business isolation is comparatively easy； inasmuch as any individual statement； any visual impression； any effect； etc。； may be abstracted without difficulty。 Much harder is the determination of its value。 If； however； we clearly recognize that it is necessary to express the exact value of each particular source of evidence； and that the task is only to determine comparative valuation； the possibility of such a thing； in at least a sufficiently close degree of certainty； must be granted。 The valuation must be made in respect of two things（1） its _*reliability_ （subjective and relative）； （2） its _*significance_ （objective and absolute）。 On the one hand； the value of the evidence itself must be tested according to the appraisement of the person who presents it and of the conditions under which he is important； on the other； what influence evidence accepted as reliable can exercise upon the _*effect_； considered in and for itself。 So then； when a testimony is being considered； it must first be determined whether the witness was able and willing to speak the truth； and further； what the importance of the testimony may be in terms of the changes it may cause in the _*organization_ of the case。
Of greatest importance and most difficult is the variation of conditions and the establishment of the changes thereby generated； with regard to the _*effect_；i。 e。： the critical interpretation of the material in hand。 Applied to a case； the problem presents itself in this wise： I consider each detail of evidence by itself and cleared of all others； and I vary it as often as it is objectively possible to do so。 Thus I suppose that each statement of the witness might be a lie； entirely or in part； it might be incorrect observation； false inference； etc。and then I ask myself： Does the evidence of guilt； the establishment of an especial trial； now remain just？ If not； is it just under other and related possible circumstances？ Am I in possession of these circumstances？ If now the degree of apparent truth is so far tested that these variations may enter and the accusation still remain just； the defendant is convicted： but only under these circumstances。
The same procedure here required for the conduct of a complete trial； is to be followed also； in miniature； in the production of particulars of evidence。 Let us again construe an instance。 The _*effect_ now is the establishment of the objective correctness of some particular point （made by statements of witnesses； looks； etc。）。 The _*complex of conditions_ consists in the collection of these influences which might render doubtful the correctnessi。 e。； dishonesty of witnesses； defective examination of locality； unreliability of the object； ignorance of experts； etc。 It is necessary to know clearly which of these influences might be potent in the case in hand； and to what degree。 The _*standardization_ consists； also this time； in the comparison of the conditions of the present case with those of other cases。 The _*variation_； again； consists in the abstraction from the evidence of those details which might possibly be incorrect； thus correcting it； from various points of view； and finally； in observing the _*effect_ as it defines itself under this variety of formulation。
This procedure； adopted in the preparation and judgment of each new piece of evidence； excludes error as far as our means conceivably permit。 Only one thing more is needfula narrow and minute research into that order of succession which is of indispensable importance in every natural science。 ‘‘Of all truths concerning natural phenomena； those whic