Abstract

This dissertation describes and assesses Karl Popper's commonsense realism. The evaluation focuses upon his arguments against nonrealism in modern physics rather than his purely philosophical arguments. Motivated by a few central concepts, Popper presented a detailed critique of the orthodox interpretation of physics. He created a "quantum mechanics without an observer" based upon an "epistemology without a subject." ;Popper believed that certain philosophical presuppositions were necessary for progressive and objective science. He claimed that a "serious crisis exists in modern physics" due to the suspension of realism. Popper subsequently presented an elaborate reinterpretation of quantum theory in attempt to reinstate a realistic and objectivist conceptual framework. He also supported the EPR thought experiment which he was convinced demonstrated the incompleteness of quantum theory and the subsequent unnecessary nonrealistic interpretation. ;Important presuppositions and contraints of Popper's realism not explicit in his purely philosophical work are manifested in his philosophical physics. The EPR test proposal crystallized his argument against positivism in physics. Thus, in light of the recent testing of the EPR paradox, I evaluate Popper's philosophical presuppositions and inquire whether classical realism needs revision. ;The dissertation's goal is this assessment of Popper's concepts underlying his attack upon modern physics. Rather than an abstract analysis of his concepts, I assess them in the context of the current quantum theoretical debates and recent testing of the EPR proposal. ;The dissertation is in the "history of ideas" style. I describe Popper's general philosophy of science, the challenge to his realism by modern physics and the Copenhagen Interpretation, Popper's realistic reinterpretation of quantum theory and the inadequacies of this project . I then evaluate his commonsense realism on the basis of his presuppositions of his project. I conclude that Popper's constraints were norms derived from classical science and were overly dependent upon intuitive, traditional notions. These constraints then can be incompatible with counter-intuitive notions of contemporary theoretical science. I also suggest that Popper's ontological dichotomies are biased by classical notions