It eventually led him to refute some of Zeno's paradoxes. Other relevant examples of potential infinities include Galileo's paradox and the paradox of Hilbert's hotel. The notion that infinite regress and infinite progress only manifest themselves potentially pertains to fallibilism. According to philosophy professor Elizabeth F. Cooke, fallibilism embraces uncertainty, and infinite regress and infinite progress are not unfortunate limitations on human cognition, but rather necessary antecedents for knowledge acquisition. They allow us to live functional and meaningful lives. Critical rationalism In the mid-twentieth century, several important philosophers began to critique the foundations of logical positivism. In his work The Logic of Scientific Discovery (1934), Karl Popper, the founder of critical rationalism, tried to solve the problem of induction by arguing for falsifiability as a means to devalue the verifiability criterion. He adamantly proclaimed that scientific truths are not inductively inferred from experience and conclusively verified by experimentation, but rather deduced from statements and justified by means of deliberation and intersubjective consensus within a particular scientific community. Popper also tried to resolve the problem of demarcation by asserting that all knowledge is fallible, except for knowledge that was acquired by means of falsification. Hence, Popperian falsifications are temporarily infallible, until they have been retracted by an adequate research community. Although critical rationalists dismiss the fact that all claims are fallible, they do belief that all claims are provisional. Counterintuitively, these provisional statements can become conclusive once logical contradictions have been turned into methodological refutations. The claim that all assertions are provisional and thus open to revision in light of new evidence is widely taken for granted in the natural sciences. Popper insisted that verification and falsification are logically asymmetrical. However, according to the Duhem-Quine thesis, statements can neither be conclusively verified nor falsified in isolation from auxiliary assumptions (also called a bundle of hypotheses). As a consequence, statements are held to be underdetermined. Underdetermination explains how evidence available to us may be insufficient to justify our beliefs. The Duhem-Quine thesis should therefore erode our belief in logical falsifiability as well as in methodological falsification. The thesis can be contrasted with a more recent view posited by philosophy professor Albert Casullo, which holds that statements can be overdetermined. Overdetermination explains how evidence might be considered sufficient for justifying beliefs in absence of auxiliary assumptions. Philosopher Ray S. Percival holds that the Popperian asymmetry is an illusion, because in the action of