If we understand by the term cause the axiom that every change has an occasion, hence that every event is bound up with a number of conditions which when lacking in whole or in part would prevent the appearance of the event, while their presence would compel its appearance, then the whole business of the criminalist is the study of causes. He must indeed study not only whether and how crime and criminal are causally related, but also how their individual elements are bound to each other and to the criminal; and finally, what causation in the criminal, considered with regard to his individual characteristics, inevitably led to the commission of the crime. The fact that we deal with the problem of cause brings us close to other sciences which have the same task in their own researches; and this is one of the reasons for the criminalist’s necessary concern with other disciplines. Of course no earnest criminalist can pursue other studies for their own sake, he has no time; but he must look about him and study the methods used in other sciences. In the other sciences we learn method, but not as method, and that is all that we need. And we observe that the whole problem of method is grounded on causation. Whether empirically or aprioristically does not matter. We are concerned solely with causation. In certain directions our task is next to the historians’ who aim to bring men and events into definite causal sequence. The causal law is indubitably the ideal and only instructive instrument in the task of writing convincing history, and it is likewise without question that the same method is specifically required in the presentation of evidence. Thus: “This is the causal chain of which the last link is the crime committed by A. Now I present the fact of the crime and include only those events which may be exclusively bound up with A’s criminality--and the crime appears as committed. Now again, I present the fact of the crime and exclude all those events which can without exception be included only if A is not a criminal--and there is no crime.”[130]