By David Kelley

Knowledge must be grounded in evidence in accordance with epistemological principles. This monograph distinguishes two kinds of principle: rules of evidence and rules of justification.

Rules of evidence, such the canons of inductive and deductive logic, specify what sort of evidence is relevant to what sort of conclusion. Rules of justification specify what a person's cognitive state must be if he is to be justified in accepting a conclusion. This distinction makes it possible to explain how our knowledge can be fully justified all the way down to its foundations in perception.

About David Kelley:

David Kelley is a professional philosopher, teacher, and author. After earning a Ph.D. in philosophy from Princeton University in 1975, he taught philosophy at Vassar College (1975-84) and at Brandeis University as a Visiting Lecturer (1989-90), specializing in epistemology and cognitive science. In 1990 Kelley founded The Atlas Society to promote open Objectivism—Ayn Rand’s philosophy of reason, achievement, rational self-interest, and freedom.

Among his books are The Evidence of the Senses, a treatise on the perceptual base of knowledge; The Art of Reasoning, a college textbook in logic, now in its 4th edition; Unrugged Individualism: The Selfish Basis of Benevolence; and A Life of One's Own: Individual Rights and the Welfare State, a critique of the moral premises of the welfare state; and Truth and Toleration in Objectivism.

Kelley has also written extensively for major publications on issues in philosophy, culture, and politics; and given many talks to academic and policy organizations.