Fechner's views are related to, and, to some extent, dependent upon, certain ones of Zoellner adduced in connection with a consideration of sun-spots.[104] Du Prel, who also acknowledges special indebtedness to Zoellner, attempted in his "Struggle for Existence in the Heavens" ("Der Kampf ums Dasein am Himmel") to demonstrate the fact of a struggle and selection among the heavenly bodies analogous to that claimed for life upon the earth. The title of the book was afterwards changed to "The History of the Evolution of the Universe,"[105] its scope having "grown far beyond the limit of the former title." Du Prel finds one of the chief advantages of an application of Darwinian ideas to astronomy in the fact that, unlike our earth, the heavens in their immensity afford us existing, or to our eye existing, examples of the various stages of their evolution, in nebular mist, comets, suns, fixed stars, planets, rings, and moons,--all subject to processes of development, which we may to some extent observe. In the first chapter of this book, Du Prel says: "The existing condition of the Cosmos with respect to all forms of the Purposeful[106]--whether we regard the realm of the organic or the inorganic--can be looked upon only as an attained, moving equilibrium of forces. Immanent in Nature lies the capacity to develop from chaotic conditions to teleologic forms; for, in the ceaseless play of forces, all other than such combinations are by their nature given over to destruction, while it lies, on the contrary, in the essence of all purposeful combinations to be preserved. In every system of mechanical forces an adjustment of the same must finally be arrived at through the removal of all immanent oppositions." "_It is impossible_ for nature to remain in chaotic conditions." "Every system of forces tends to a state of equilibrium. This is as true of the conflict of images in a human brain, from whose mutual accommodation the resultant of a unified theory of the universe arises, as of oppositions in the social organism, of the conditions of power and civilization of neighboring peoples, of the meteorologic states of the earth, of the mechanical forces of a solar system, or the atoms of a cosmic mist. Every war of the elements ends with an adjustment of ideal justice, for every 'moment' of force has influence proportioned to its power and the duration of its activity."[107]