> The word jhana comes from Buddhist scriptures, where they were first described. However, as many meditators like to point out, jhanas predate Buddhism. ... I am not a Buddhist, nor would I describe myself as a meditator.
She seems to be taking pains to extract Buddhist techniques from Buddhism, and discuss them independently. Even if these practices predate Buddhism, Buddhism is the system of thought that contextualizes them, and has been developed and enriched over thousands of years, to provide a systematic framework for understanding them. This is especially true of Zen Buddhism—the word "Zen" is even derived from "jhana."
It'd be like if you tried to describe the properties of sulfur dioxide or something, without acknowledging that an entire academic discipline—chemistry—has been doing that for centuries. You don't have to "be a Buddhist" to study Buddhism, any more than you have to be a chemist to study chemistry.