In the second place, we have the "stable bridge." This does not help us appreciably over the difficulty, but we have a right to use it as a bridge between rigid stability and motion. Unfortunately stability consists in absence of motion, and the question as to the generation of motion remains as dark a secret as before. And if Herr Duehring shifts his no-movement at all to universal movement in infinitely small particles and ascribes to this ever so long a duration of time, we are still not the thousand part of an inch further from the place whence we started. Without a creative act we can get nothing from nothing, not even anything as small as a mathematical differential. The bridge of stability is therefore not even a _pons asinorum_. Herr Duehring is the only person able to cross it. Thirdly, as long as the present theories of mechanics prevail, this constitutes one of Herr Duehring's most reliable props, we cannot indicate how anything passes from a state of quiescence to one of motion. But the mechanical theory of heat teaches us that the movement of the mass depends upon the movements of the molecules, (so that even in this case movement proceeds from other movement and not from lack of movement) and this Herr Duehring shyly points out might serve as a bridge between the entirely static (the state of equipoise) and the dynamic (self-movement). But here Herr Duehring leaves us entirely in the dark. All his deepening and sharpening has dug a pit of folly and we are brought up necessarily in "darkness." But Herr Duehring troubles himself very little about that. He says right on the next page, with considerable audacity that he has been able to endow the self contained stability with real significance by means of the properties of matter and the mechanical forces. In spite of all these errors and confused statements we have still an inspiring faith remaining that "The mathematics of the inhabitants of other planets cannot rest on any axioms other than our own." _Cosmogony, Physics, and Chemistry._ Proceeding we come to theories respecting the mode by which the world, as it is to-day, came into being. A universal separation of matter from one element was the notion of the Ionic philosophers, but, since Kant, the conception of an original nebulous state has played a new role and according to this gravitation and heat expansion have built up the worlds, little by little and one by one. The mechanical theory of heat of our time has fixed the origin of the earlier condition of the universe with much greater precision.