The play of world-events with equal justice may be held to declare that we comprehend adequate causes as to declare that we do not comprehend them, inasmuch as all we may have comprehended as the adequate cause of any life-phenomenon, itself on its part demands an adequate cause, and so on backwards _ad infinitum_. In short, Every adequate cause is of a secondary nature. From this science argues as follows:-- It is a fact that we comprehend adequate causes, in certain respects, up to a certain degree, consequently perfect comprehension is possible, everything depending simply on patience and correct methods. With this claim of the _comprehensibility in principle_ of life-phenomena, science takes upon itself the proud task, of itself _working out a world-theory_ from the foundation upwards. Comprehensibility in principle of life-phenomenon is that standpoint with reference to actuality which is given for every science without exception. On any other hypothesis science as science has no justification whatever for its existence. Science, if it is to be what its name implies, is that which furnishes knowledge. Knowledge can only be furnished where things can be completely demonstrated, made tangible to sense. That, however, is only possible if nothing lies hidden in things that is not perceptible by sense. Hence science, if she does not wish to gainsay her own right to exist, must proceed upon the arbitrary hypothesis that _there is nothing in the play of world-events that is not perceptible to the senses_. And if really there is something of the sort there, then for her it is merely the _not yet demonstrable_, which later on, with patience, with improvements in methods, will also be achieved. This is the position which science takes up with reference to the play of world-events, the foundation on which her whole superstructure is erected. Science is possible there only where there is the sensible, the demonstrable, where there is something so constituted that I can class it with others of its kind. And all science--to put it briefly--is just the endeavour to make tangible to sense the entire play of world-events. In support of this standpoint in principle of science, I cite the following passage from W. Ostwald’s _Schule der Chemie_:-- _Pupil._ These are only properties. What I mean, however, is that which lies at the root of all properties. _Teacher._ This then ought to remain behind when you have thought away all properties from the matter. Well, think away all its properties from a piece of sugar--colour, shape, hardness, weight, taste, and so forth--what then remains over? Nothing! For it is only through its properties that I can recognize that there is something there.... You must get rid of the notion that apart from the properties of a thing there is anything at all to be found beneath them that is higher or more real than the properties.