Arnold Baise

The term “objective” has both a metaphysical and an epistemological meaning, and each of these meanings gives rise to a corresponding objective-subjective dichotomy. A formal definition of objectivity is given, and this clarifies the nature of the epistemological dichotomy. These dichotomies are represented by classes of existents, and a Venn-type diagram is used to illustrate the relationship between them. It is shown that the class of all existents can be partitioned into three mutually exclusive and exhaustive classes, which correspond to Rand's intrinsic-subjective-objective trichotomy.

The main purpose of this article is to use Ayn Rand’s analysis of the meaning of objectivity to clarify the much-discussed question of whether probability is “objective” or “subjective.” This results in a classification of probability theories as frequentist, subjective Bayesian, or objective Bayesian. The work of objective Bayesian E. T. Jaynes is emphasized, and is used to provide a formal definition of probability. The relation between probability and induction is covered briefly, with probability theory presented as the basis of inductive inference.