Historians of esotericism keep being asked to define “esotericism.” Not infrequently, this request is made against a negative background of scepticism about the topic itself and the very project of studying it. However, to expect a definition of “esotericism” is in fact problematic, and defending one even more so. To request a universal definition of “esotericism” that transcends its historical manifestations is asking too much: there is no such thing as an essence, a systematics, or a normative meaning of esotericism. It is only in the nineteenth century that the concept was established as a generic term for extra-canonical forms of religion and knowledge, from gnosis and magic to Theosophy and New Age. Essentially, there are only two ways of using the concept: a historical and a pragmatic one. A historical approach means investigating the formation and transformation of the term, its application and interpretation, from a perspective of Begriffsgeschichte (the history of concepts). A pragmatic approach means that, on such a basis, one can use the concept of esotericism in a scholarly way, provided that it is not understood – like the similar concept of “mysticism” – as an a priori or an essentialist one. It is simply a pragmatic, heuristic, historiographic tool. As such – and only as such – can it be useful and appropriate.

Both apologetics for “esotericism” and their counterparts, polemics, are even more problematic from a scholarly perspective. As a matter of principle, scholarly practice approaches its topic from a critical, analytical, distanced, “objective” stance. Apologetics and polemics, by contrast, relate to it from a deliberately subjective and tendentious perspective. Scholarship cannot take such a normative approach but is concerned with non-ideological, unbiased observation, description, and analysis. Therefore, it is not a matter of defending esotericism or its “secret knowledge,” but only of studying it historically and without prejudice.

Apologetics and polemics have no place in scholarly practice, yet they themselves may become the object of scholarly analysis. And in fact, the polemics against esotericism has a long history, from premodern theological and ecclesiastical perspectives that framed it as heretical artes prohibitae (prohibited arts) to its categorisation as “superstition” in the Enlightenment. In more recent periods too, and right up to the present, esotericism is seen from various perspectives as a controversial, tricky, precarious topic, and even the very possibility of studying it is sometimes called into question.