he is also arguing for internal evolution, similar to Roux, except emphasizing complexity as the main factor instead of strength. Thus, Dumont's pleasure in the expansion of power, Roux's internal struggle, Nägeli's drive towards complexity, and Rolph's principle of insatiability and assimilation are fused together into the biological side of Nietzsche's theory of will to power, which is developed in a number of places in his published writings. Having derived the "will to power" from three anti-Darwin evolutionists, as well as Dumont, it seems appropriate that he should use his "will to power" as an anti-Darwinian explanation of evolution. He expresses a number of times the idea that adaptation and the struggle to survive is a secondary drive in the evolution of animals, behind the desire to expand one's power – the "will to power". Nonetheless, in his notebooks he continues to expand the theory of the will to power. Influenced by his earlier readings of Boscovich, he began to develop a physics of the will to power. The idea of matter as centers of force is translated into matter as centers of will to power. Nietzsche wanted to slough off the theory of matter, which he viewed as a relic of the metaphysics of substance. These ideas of an all-inclusive physics or metaphysics built upon the will to power do not appear to arise anywhere in his published works or in any of the final books published posthumously, except in the above-mentioned aphorism from Beyond Good & Evil, where he references Boscovich (section 12). It does recur in his notebooks, but not all scholars treat these ideas as part of his thought. Will to power and eternal recurrence Throughout the 1880s, in his notebooks, Nietzsche developed a theory of the "eternal recurrence of the same" and much speculation on the physical possibility of this idea and the mechanics of its actualization occur in his later notebooks. Here, the will to power as a potential physics is integrated with the postulated eternal recurrence. Taken literally as a theory for how things are, Nietzsche appears to imagine a physical universe of perpetual struggle and force that repeatedly completes its cycle and returns to the beginning. Some scholars believe that Nietzsche used the concept of eternal recurrence metaphorically. But others, such as Paul Loeb, have argued that "Nietzsche did indeed believe in the truth of cosmological eternal recurrence." By either interpretation the