In 1983 he became known for his treatise The Beast, in which he promoted a philosophical position which was diametrically opposed to the peace movement Zeitgeist of those years: He advocated a philosophy of "escape of mankind" which aims for an early self-destruction of the human race by means of the accumulated nuclear weapons found in arsenals around the world.
It has been proved by the author's subsequent publications which are written with an attitude of nihilism and extreme distaste for the world, that The Beast was in no way, as suspected by some critics, a particularly bitter satire.
Horstmann puts forth the theory that mankind has been pre-programmed to eliminate itself in the course of history—and also all its memory of itself—through war (thermonuclear, genetic, biological), genocide, destruction of its sustaining environment, etc.
Its final meaning is the sand blown through the eye-holes of human skulls.” Through his analysis of history, he has concluded that our species is engaged in a constant process of armament, with the eventual end goal of wiping itself out through war.
“the place of a skull and charnel house of a mad, incurably bloodthirsty slaughtering, flaying and whetting, of an irresistible urge to destroy to the last.” Although inspired by the already extreme philosophy of Philipp Mainländer, Horstmann ends up with an even more explicit solution regarding the problem of human existence.