[6] The simplest kink exhibited an easily understood event horizon that led him to recognize the one in the Schwarzschild metric and eliminate its coordinate singularity.

In essence, Finkelstein determined that whatever falls past the Schwarzschild radius into a black hole cannot escape it; the membrane is one-directional.

This important work influenced the decisions of Roger Penrose and John Archibald Wheeler to accept the physical existence of event horizons and black holes.

His early quantum space-times proving unphysical, he later studied chronons with a regularized form of Bose–Einstein statistics due to Tchavdar D.

[1][2][13][14] Influenced by his discussions of Buddhist philosophy at the Mind and Life dialogues, Finkelstein developed a philosophical theory of "universal relativity" which he thought might help advance physics.