ABSTRACT
Inductive inference is a matter of weighing evidence and judging likelihood, not of proof. How do we go about making these non-demonstrative judgments, and why should we believe they are reliable? Both the question of description and the question of justification arise from underdetermination. To say that an outcome is underdetermined is to say that some information about initial conditions and rules or principles does not guarantee a unique solution. The information that Tom spent five dollars on apples and oranges and that apples are fifty cents a pound and oranges a dollar a pound under-determines how much fruit Tom bought, given only the rules of deduction. Similarly, those rules and a finite number of points on a curve underdetermine the curve, since there are many curves that would pass through those points.
