Originally posted 4/8/22, Revised 6/14/22
Philosophically, along with the newly developed logical positivism, British and Continental idealism as well as phenomenology were very popular. Early 1900s Europe was a period of spiritual experimentation, and the enlightenment had for the most part completely left (existing in a semi state throughout German idealism). The early 1900s had developments in not only the esoteric organizations but there was also an interest in alternative religions. Rather than the familiar Greek philosophy, they were more interested in philosophy from other continents. The general consensus is that there is uncharted philosophy from other continents, so it is a good idea to come to understand that philosophy. The early 1900s were still coming off of the heavy critiques of paganism from late antiquity, so rather than getting absorbed in this, it was considered much more tasteful for the spiritually adventurous to get absorbed in Indology, sinology, and Islamology. And European paganism (especially the Greek variant) and also Satanism have a very hard edge to them. It is true that Hinduism is pagan, but the pagan of the Hindus is much more relaxed than the European (especially the Greek) variants.
The distinguishing feature of the European exposure to alternative religions was its trend (through Indology, sinology, and Islamology) to treat the religion exactly in the state it was developed in its philosophical state, treating alternative issues such as history and Western philosophy. This is in contrast to the esoteric approaches of the Americas and adoptions to popular audiences which was popular with American spirituality. Thus the three main trends among Europeans in the early 1900s were Indology, Islamology, and sinology. It is true that the English tend to the Indologists, the Germans tend to be the sinologists, and the Italians tended to be the Islamologists. Right in the middle of everything was France, which participated extensively in all three. And some of the greatest of these can be found among the French. However, Indology, for example, can be found in both Germany with, for example, Heinrich Zimmer, and in Italy with the works of Julius Evola (technically, Julius Evola located his work on Hinduism half way between the Indological approach and the esoteric approach). Also produced in the early 1900s were such juggernauts as the massive Romanian historian of religion Mircea Eliade.