It is true that several teleological naturalists, feeling the scientific insufficiency of a supernatural “_creation_,” have endeavoured to save the hypothesis by wishing it to be understood that creation “is nothing else than a way of coming into being, unknown and inconceivable to us.” The eminent Fritz Müller has cut off from this sophistic evasion every chance of escape by the following striking remark:—“It is intended here only to express in a disguised manner the shamefaced confession, that they neither have, nor care to have, _any opinion_ about the origin of species. According to this explanation of the word, we might as well speak of the creation of cholera, or syphilis, of the creation of a conflagration, or of a railway accident, as of the creation of man.” (Jenaische Zestscrift, bd. v. p. 272.) In the face, then, of these hypotheses of creation, which are scientifically insufficient, we are forced to seek refuge in the _counter-theory of development_ of organisms, if we wish to come to a rational conception of the origin of organisms. We are forced and obliged to do so, even if the theory of development only throws a glimmer of probability upon a mechanical, natural origin of the animal and vegetable species; but all the more if, as we shall see, this theory explains all facts simply and clearly, as well as completely and comprehensively. The theories of development are by no means, as they often falsely are represented to be, arbitrary fancies, or wilful products of the imagination, which only attempt approximately to explain the origin of this or that individual organism; but they are theories founded strictly on science, which explain in the simplest manner, from a fixed and clear point of view, the whole of organic natural phenomena, and more especially the origin of organic species, and demonstrate them to be the necessary consequences of mechanical processes in nature. As I have already shown in the second chapter, all these theories of development coincide naturally with that general theory of the universe which is usually designated as the uniform or _monistic_, often also as the _mechanical_ or causal, because it only assumes mechanical causes, or _causes working by necessity_ (causæ efficientes), for the explanation of natural phenomena. In like manner, on the other hand, the supernatural hypotheses of creation which we have already discussed coincide completely with the opposite view of the universe, which in contrast to the former is called the twofold or _dualistic_, often the _teleological_ or vital, because it traces the organic natural phenomena to final causes, acting and _working for a definite purpose_ (causæ finales). It is this deep and intrinsic connection of the different theories of creation with the most important questions of philosophy that incites us to their closer examination.