Columbia subject headings:
Knowledge, Theory of.
Ortega y Gasset, José, 1883-1955.
Wittgenstein, Ludwig, 1889-1951.
Harvard subject headings:
Belief and doubt--Congresses.
Knowledge, Theory of--Congresses
Ortega y Gasset, José, 1883-1955--Congresses.
Pluralism--Congresses.
Rationalism--Congresses.
Reason--Congresses.
Relativity--Congresses.
Wittgenstein, Ludwig, 1889-1951--Congresses.
Princeton subject headings: