“The life and work of the German chemist and philosopher Wilhelm Ostwald (1853–1932) is studied from the angle of scientism. In Ostwald's case scientism amounted to: (i) the construction of a unified science of nature (energetics); (ii) its use as the ‘scientific’ basis for an all-embracing philosophy or world-view (energeticism); (iii) 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’ (on prayer and on Christmas), 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.”

“According to received historiography, the fundamental issue in eighteenth-century optics was whether light could be understood as the emission of particles or as the motion of waves in a subtle medium. Moreover, the emission theory of light was supposed to have been dominant in the eighteenth century, backed by Newton's physical arguments. This picture is enriched and qualified by focusing on the origins, contents, and reception of Leonhard Euler's wave theory of light published in 1746, here studied in depth for the first time. Contrary to what has been assumed, in an important sense, the particle-wave debate only starts with Euler. In addition, Euler's wave theory was the most popular theory in Germany for thirty-five years. Finally, when the emission view of light suddenly became dominant in Germany around 1795, new chemical experiments were crucial. Reflecting on the mathematical, experimental, and metaphysical aspects of physical optics, Casper Hakfoort provides as an epilogue a general picture of early modern science.”

“As Casper showed in his article ‘The Historiography of Scientism: A Critical Review’ (1995), the notion of scientism in a variety of meanings has been around for a long time; still, Casper put it to new uses by applying it to persistent efforts over the centuries, from Hobbes and d’Holbach to Capra and Hawking in our own day, to make the latest science serve the construction of a world-view.”

“That theme he finally took the philosophical significance of science in modern society, to be more precise, the tendency of scientists to their theories, valid for a limited domain of reality, to build up complete worldviews and philosophies out. Both this phenomenon, also known as scientism, as the political counterpart, technocracy, Hakfoort ran against the grain and therefore deserved further investigation. His case he found in the late nineteenth-century ideas of the great German chemist and later Nobel laureate Wilhelm Ostwald. Ostwald strove his energetic teaching, which he saw as the basis for the whole of physics and chemistry, to build a comprehensive worldview. To this end, Ostwald designed amongst much more energetic happiness formula and he propagated energetic Sunday Meetings with associated rituals and chants, replacing traditional Christian worship. Hakfoort created, there is usually a great pleasure at hearing his lectures so far to get them singing along Ostwald replacement carols lustily. His most important publication on this subject, it is now almost be called classic 'Science deified Wilhelm Ostwald Energeticist world-view and the History of Scientism', published in 1992 in Annals of Science.”