Concepts of the Universe
The atheistic hypothesis of eternal self-existence was not an answer as it failed to offer an explanation of the universe; moreover, infinite past time was ruled out as 'absolutely unthinkable'. Herbert Spencer, the influential philosopher of evolution par excellence, was not a scientist but he was considered to belong to the group of British scientific naturalists. William Thomson was not only a pioneer of thermodynamics, he was also a devout Christian; yet he had no doubt that the universe is spatially infinite. Concerning the more general relationship between cosmology and physics, Pierre Duhem claimed that the two fields are so different that physical theory cannot be meaningfully applied to cosmology. The romantic or neo-romantic features of positivism appeared clearly in the energetics movement which under the leadership of Wilhelm Ostwald and Georg Helm became an important part of German scientific and cultural life at the end of the century.