The life and work of the German chemist and philosopher Wilhelm Ostwald is studied from the angle of scientism. In Ostwald's case scientism amounted to: the construction of a unified science of nature ; its use as the ‘scientific’ basis for an all-embracing philosophy or world-view ; the programme to realize this philosophy in practice, as a secular religion to replace Christianity. Energetics, a generalized thermodynamics, was proposed by Ostwald and others to replace mechanics as the fundamental theory in physical (...) science. Its contents and fortunes are briefly discussed. Ostwald's energeticist philosophy is illustrated by his classification of the pure sciences, his theory of happiness and his science-based ethics. Ostwald cherished a metaphysics in which energy and energy transformations were fundamental to all phenomena and processes. As a result, he transferred his optimism about science and technology to energeticism: philosophical, psychological and ethical questions were regarded as capable of solution by his scientistic philosophy. The practice of Ostwald's energeticism is illustrated by two of his ‘Sunday sermons’ , as well as by a public lecture on science. He considered science the modern and legitimate substitute for God and claimed that science was, or would soon be, omnipresent, eternal, almighty, omniscient and perfectly good. Ostwald's substitute religion of science suggests the question, discussed in the last section of this paper, to what extent and in what sense historians might fruitfully interpret scientism as a secular religion. (shrink)

In the second half of the eighteenth century a lively debate was going on in Germany about the nature of light. One important contribution to this discussion, namely a paper by Nicolas Béguelin, is studied in this article. In his essay, Béguelin compared the Newtonian emission theory of light and the wave theory of Leonhard Euler. Whereas others opted for one of the two theories by invoking arguments or authorities, Béguelin made a systematic search for experiments which he hoped would (...) settle the dispute. Two of these experiments were most original. The first, which Béguelin himself performed, concerned light rays grazing a glass surface. For several reasons it did not have the impact it deserved. The second one was a thought experiment which was meant to illustrate a major tenet of the wave theory, that is, the analogy between light and sound. An analysis is given of these two experiments, and it is shown that neither of them brought the debate to an end. (shrink)