This term has been covered by the website Wikipedia as "Intuitive Music"
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Intuitive music is a form of musical improvisation based on instant creation in which fixed principles or rules may or may not have been given. It is a type of process music where instead of a traditional music score, verbal or graphic instructions and ideas are provided to the performers (Stockhausen 1989, 113–14). The concept was introduced in 1968 by the German composer Karlheinz Stockhausen (Stockhausen 1993; Bergstrøm-Nielsen 1997), with specific reference to the collections of text-notated compositions Aus den sieben Tagen (1968) and Für kommende Zeiten (1968–70). The first public performance of intuitive-music text compositions, however, was in the collective work Musik für ein Haus, developed in Stockhausen's 1968 Darmstadt lectures and performed on 1 September 1968, several months before the first realisations of any of the pieces from Aus den sieben Tagen (Iddon 2004, 91, 99; Misch and Bandur 2001, 478; Stockhausen 2009, 3).
Intuitive music may appear to be synonymous with free improvisation or with improvised playing within open composition forms, but the collectively intuitive aspect, the emancipation from known music genres and the meditative dimension are especially emphasized by Stockhausen: "I try to avoid the word improvisation because it always means there are certain rules: of style, of rhythm, of harmony, of melody, of the order of sections, and so on" (Stockhausen 1989, 113). Nevertheless, one critic finds that intuitive music is not in essence irrational, but that for Stockhausen intuition must become a controllable ability, and therefore is an instrument of the project of modernity: "the investigation and instrumentalization of the world by controlled procedures" (Kutschke 1999, 155).
At the 1968 Darmstadt composition seminar where the intuitive-music concept was central for the group composition Musik für ein Haus, Stockhausen himself emphasised that it has nothing to do with indeterminacy: "I do not want a spiritualistic seance—I want music! I do not mean anything mystical, but everything absolutely direct, from concrete experience. What I have in mind is not indeterminacy, but intuitive determinacy!" (Ritzel 1970, 15; translated by Richard Toop in Kurtz 1992, 164).