Presuppositions of Enquiry

Abstract

A person who grew up and lives in a certain limited environment has time and again encountered bodies of fairly constant size and shape, color, taste, gravity and so on. Under the influence of his environment and the power of association he has become accustomed to find the same sensations combined in one place and moment. Through habit and instinct, he presupposes this constant conjunction which becomes an important condition of his biological welfare. The constant conjunctions crowded into one place and time that must have served as foundation for the idea of absolute constancy or substance are not the only ones. An impelled body begins to move, impels another and starts it moving; the contents of an inclined vessel flow out of it; a released stone falls; salt dissolves in water; a burning body sets another alight, heats metal until it glows and melts, and so on. Here too we meet constant conjunctions, except that there is more scope for spatio-temporal variation.