Ours is a field in crisis. Artificial Intelligence cannot make up its collective mind whether it is a discipline of Science or of Engineering. It is unclear from our literature and from our research whether our goals are to explain intelligence or to create it. A researcher who hypothesizes about the structure of intelligent behavior is accused of constructing theories without hope of instantiation; one who creates a seemingly intelligent artifact often sees it derided as "mere hackery." The theorists among us confer in an ever more arcane language, grasping for the idealized agents and environments for which our formal analyses might hold, while those of us who build artifacts have been forced into the back alleys, alchemists unwilling and unable to divulge our dark arts. The tensions created by this uncertainty regarding our role as a field of research threaten to tear our community apart. Now our bright knight has come in the unlikely guise of a philosopher and mathematician. Kyburg sets out on what seems the most Scientific of endeavors: to produce a theoretical analysis of belief given evidence. He proposes to explore a particular theory of belief based on evidential probability. He then proceeds to detail various aspects of the theory and their consequences. His goal would appear to be a hypothesis-ideally testable- tat, if true, explains intelligent belief. but what is this analytic Truth at which he arrives? Kyburg's philosophical arguments about abstract, theoretical, and foundational issues lead to shockingly pragmatic conclusions. In resolving such critical issues as the requisite degree of practical certainty or the infinite regress of evidential support-in grounding and justifying his theories- he ultimately defers to the empirical: We need not worry about infinite regress because there is in practice a limit to how fine a distinction we can make. His elaborate philosophical framework for understanding and interpreting belief rests on its grounding in real-world experience. Kyburg appeals to engineering on seeral fronts: -to stop the infinite regress of evidential justification -to set the sufficient level of practical certainty -to ground his analysis in the "objective truth" of mathematics -to argue for the acceptance of contingent statements