Date of Award


Degree Type


Degree Name

Bachelor of Science (BS)



First Advisor

Yongsheng Xu


As a central tenet of falsificationism, Karl Popper holds that all possible scientific theories individually have a probability equal to zero. Popper’s position rests upon the Principle of Indifference, the equiprobability of mutually exclusive outcomes, to derive this zero probability. In this paper, I will illustrate that the Principle of Indifference fails to compute objective probabilities in cases in which an epistemic agent faces ignorance. Prior to experience, there is no sufficient reason to prefer any probability distribution to any other; yet, the Principle of Indifference implies a preference for a uniform probability distribution. Distribution preference is determined by the relevant experience and rational expectations of epistemic agents. Relevant experience is defined by observations and other sense experience regarding the relevant trial. Rational expectations represents the non-arbitrarity of distribution preference. Without rational expectations, the distribution preference is arbitrary even when informed by experience. If an agent lacks relevant experience, then any distribution preference is arbitrary; however, if an agent possesses relevant experience, then the Principle of Indifference does not apply. A rejection of the Principle of Indifference undermines the necessity of zero probabilities for scientific theories in which case Popper’s conclusions of falsificationism do not follow. Objective probability, then, understood within the logical interpretation, is a problematic notion.