 Carnap, Rudolf |  Goodman, Nelson: aesthetics |  induction: problem of |  Leśniewski, Stanisław |  Lewis, Clarence Irving |  logic: conditionals |  mathematics, philosophy of: nominalism |  mereology |  nominalism: in metaphysics |  Platonism: in the philosophy of mathematics |  Quine, Willard Van Orman |  reflective equilibrium |  relativism |  Russell, Bertrand |  Vienna Circle |  Whitehead, Alfred North 