Knowledge of the external world is said to be secured in an objective fashion according to the principles of proof, refutability, and those canons of science which can be traced to Newton's four published Rules of Reasoning in Natural Philosophy. Much of scientific reasoning, however, especially in the human sciences, involves propositions incapable of either verification or falsification; yet belief in and commitment to unprovable propositions obviously influence scientific work and provide the basis for schools of thought. Political theories are organizations of subjective assertions which, along Q methodological lines, can be shown to be structured, thereby giving empirical substance to Newton's unpublished Fifth Rule. As a demonstration, leading hypotheses concerning the nature of political society are collected, and the views of major political theorists (Plato, Locke, Marx, et al.) are each modeled as Q sorts. Correlation then demonstrates the interconnections among these schools of thought, and factor analysis points to the intellectual traditions of Western political philosophy. Q sorts obtained from citizens from a variety of walks of life demonstrate the extent to which these traditions have penetrated the public mind. (Author)