Evidently the finding of causes involves, according to the complexities of the case, a varying number of subordinate tasks which have to be accomplished for each particular incident, inasmuch as each suspicion, each statement _pro_ or _con_ has to be tested. The job is a big one but it is the only way to absolute and certain success, provided there is no mistake in the work of correlating events. As Schell says: “Of all the observed identities of effect in natural phenomena only one has the complete strength of mathematical law--the general law of causation. The fact that everything that has a beginning has a cause is as old as human experience.” The application of this proposition to our own problem shows that we are not to turn the issue in any unnecessary direction, once we are convinced that every phenomenon has its occasion. We are, on the contrary, to demonstrate this occasion and to bring it into connection with every problem set by the testimony at any moment. In most cases the task, though not rigidly divided, is double and its quality depends upon the question whether the criminal was known from the beginning or not. The duality is foremost, and lasts longest if only the deed itself is known, and if the judge must limit himself entirely to its sole study in order to derive from it its objective situation. The greatest mistakes in a trial occur when this derivation of the objective situation of the crime is made unintelligently, hastily or carelessly, and conversely the greatest successes are due to its correct rendering. But such a correct rendering is no more than the thorough-going use of the principle of causality. Suppose a great crime has been committed and the personality of the criminal is not revealed by the character of the crime. The mistake regularly made in such a case is the immediate and superficial search for the personality of the criminal instead of what should properly proceed--the study of the causal conditions of the crime. For the causal law does not say that everything which occurs, taken as a whole and in its elements, has one ground--that would be simply categorical emptiness. What is really required is an efficient and satisfying cause. And this is required not merely for the deed as a whole but for every single detail. When causes are found for all of these they must be brought together and correlated with the crime as described, and then integrated with the whole series of events.