Arthur Schopenhauer's The World as Will and Idea was first published in 1819, and its second edition in 1844. In 1963, three months before she began channeling Seth, Jane Roberts composed a piece of automatic writing with a similar title, "The Physical Universe As Idea Construction". This was to be the nucleus of the complete body of work later elaborated in her channeled and unchanneled writings.
There are some interesting parallels between Schopenhauer's philosophy and the Roberts/Seth material. Seth identifies the nature of being and consciousness as action, while Schopenhauer states that the nature of matter is action and causation, and that it, like time and space, is an idea of perception (consciousness). In a pre-Einsteinian intimation of the relativistic space-time continuum, he explains that time, space, matter and causality are all forms of the principle of sufficient reason, and that matter, or mass, is nothing other than the union of space and time. Seth explains how physical time and space flow from psychological time and space, the outer from the inner, while Schopenhauer describes time and space as categories of the "understanding", Verstand, and frameworks of "perception", Anschauung, which in German also means "intuition", "insight", "outlook" and "perspective".
The fact that all these meanings are carried by a single word in his language perhaps explains why he does not clearly distinguish between the inner and outer senses; it is often unclear whether he is referring to actual, external perceptions or to mental images. He certainly attributes things to Anschauung which go beyond mere sense-perception, such as solving physics problems and designing complex mechanical systems. The relationship between the terms is expressed thus:
"All intuitive perception [Anschauung] is intellectual, for without the understanding [Verstand] we could never achieve intuitive perception," thus implying a formal contribution of the brain to the Anschauung. In the second volume of his Die Welt als Wille und Vorstellung, Schopenhauer says that "perception is not only the source of all knowledge, but is itself knowledge... it alone is the unconditionally true genuine knowledge." We can interpret his use of the word Verstand to mean the operation undertaken by the brain and leading to the intuitive perception [Anschauung], since Schopenhauer tells us that "the forms underlying Verstand, the Verstand is a function of the brain." http://webexhibits.org/causesofcolor/1D.html
In comparison, Seth presents a detailed list of Inner Senses, which are fleshed out still further by Elias. These senses depend not upon the brain alone, but also upon nonphysical apects of the self, although they are received and processed through the brain.