Inasmuch as the work of the criminal judge depends upon the proof of evidence, it is conceivable that the thing for him most important is that which has evidential character or force.[142] A sufficient definition of evidence or proof does not exist because no bounds have been set to the meaning of “Proved.” All disciplines furnish examples of the fact that things for a long time had probable validity, later indubitable validity; that again some things were considered proved and were later shown to be incorrect, and that many things at one time wobbly are in various places, and even among particular persons, supposed to be at the limits of probability and proof. Especially remarkable is the fact that the concept of _the proved_ is very various in various sciences, and it would be absorbing to establish the difference between what is called proved and what only probable in a number of given examples by the mathematician, the physicist, the chemist, the physician, the naturalist, the philologist, the historian, the philosopher, the lawyer, the theologian, etc. But this is no task for us and nobody is called upon to determine who knows what “Proved” means. It is enough to observe that the differences are great and to understand why we criminalists have such various answers to the question: Is this proved or only probable? The varieties may be easily divided into groups according to the mathematical, philosophic, historical or naturalistic inclinations of the answerer. Indeed, if the individual is known, what he means by “proved” can be determined beforehand. Only those minds that have no especial information remain confused in this regard, both to others, and to themselves. Sharply to define the notion of “proved” would require at least to establish its relation to usage and to say: What we desire leads us to an _assumption_, what is possible gives us _probability_, what appears certain, we call _proved_. In this regard the second is always, in some degree, the standard for the first (desires, e.g., cause us to act; one becomes predominant and is fixed as an assumption which later on becomes clothed with a certain amount of reliability by means of this fixation). The first two fixations, the assumption and the probability, have in contrast to their position among other sciences only a heuristic interest to us criminalists. Even assumptions, when they become hypotheses, have in various disciplines a various value, and the greatest lucidity and the best work occur mainly in the quarrel about an acutely constructed hypothesis.