Richard Sylvan / Bertrand Russell Nicolai Hartmann / Charles S. Peirce / Ludwig Wittgenstein / Roman Ingarden / Bertrand Russell / Alfred North Whitehead / Ludwig von Bertalanffy / Bernard Bolzano / Jon Barwise / Richard Routley / Nelson Goodman / Arthur Norman Prior / Konrad Lorenz / Edmund Husserl / Raul Corazzon / Gustav Bergmann / Martin Heidegger / Charles Hartshorne / Hector-Neri CastaƱeda / Willard Van Orman Quine / Franz Brentano / Fred Sommers Hector-Neri / Roman Suszko Fred Sommers / Roman Suszko / Justus Buchler / David Malet / /