Mesmer was the first to propose a rational basis for the effects of hypnosis.
Although we now know that his notion of “animal magnetism”, transferred from healer to patient through a mysterious etheric fluid, is hopelessly wrong, it was firmly based on scientific ideas current at the time, in particular Isaac Newton’s theories of gravitation.
These practices tend to be for magical or religious purposes, such as divination or communicating with gods and spirits.
It’s important to remember, however, that what we see as occultism was the scientific establishment of its day, with exactly the same purpose as modern science – curing human ills and increasing knowledge.
At the same time, the style of hypnosis changed, from a direct instruction issued by an authoritarian figure (a legacy of the charismatic mesmerist) to a more indirect and permissive style of trance induction, based on subtly persuasive language patterns.