Noumenon, the Album, listen here:
Music by Wim

In philosophy, a noumenon (/ˈnuːmənɒn/, UK also /ˈnaʊ-/; from Greek: νoούμενον; pluralnoumena) is a posited object or event that exists independently of human sense and/or perception.[1] The term noumenon is generally used in contrast with, or in relation to, the term phenomenon, which refers to any object of the senses. (Source: wikipedia)

Never heard of the word noumenon, ’till I opened the URTEXT of A Course In Miracles. On the first page you will read the word noumenon in the version I started reading(see below).

“The thing in itself” is used in the fifth miracle principle: This is why ‘the thing in itself’ does not matter. The only thing that matters is the Source, and this is far beyond human evaluation.

The “thing in itself” is a term used in Philosophy to refer to a noumenon which is distinct from a phenomenon. A phenomenon is that which is perceived; a noumenon is the actual object that emits the phenomenon. (Urtext- miracles in action, 2008)

Enjoy the album! Love Wim