From 1977 to 1990 Holenstein taught philosophy at the Ruhr University in Bochum, Germany, then at ETH Zurich until his retirement in 2002 when he moved to Yokohama, Japan.
Holenstein's early philosophical analyses strive to clarify the processes involved in cognition, especially in associations, that occur "without the (conscious and volitional) participation of the I."
Inspired by the Swiss philosopher Anton Marty, Jakobson, and Greenberg, Holenstein deals in depth with putative language universals, and their possible understanding.
Based on the methodological perspectives that Holenstein had gained in the years of his linguistic scholarly endeavors, he undertook the comparative investigation of cultural phenomena.
The call to the ETH Zurich led Holenstein to complement his cultural philosophical investigations by a series of studies that relate to typical traits of the Swiss political system.
This is supported by the international prestige of its two main minority languages and the actual privileging of all three of them, as well as by the fortunate fact that political, linguistic, denominational and economic frontiers do not coincide.
He addressed issues, furthermore, concerning traditional social covenants such as agreements between employers’ and employees’ associations, mediation, mutual acceptance of diverse laws in the cantons, informal ideals like good faith and fairness, free movement, neutrality in case of a global conflict between civilizations, and the historical background of the invocation of God in the constitution's preamble.
Like his language-oriented philosophical studies, also Holenstein's few texts that relate to ethics center on cognitive issues: Conscience, moral feelings, and sense of responsibility.