This scholarly book presents and critically evaluates the outstanding contributions of both cognitive psychology and artificial intelligence to our understanding of the nature of intelligence and intelligent systems. Examining conceptual thought across the domains of reasoning and logic, language and analogy, and scientific discovery, Wagman compares human reasoning with computer reasoning. Of special interest to readers is the general critique of artificial intelligence research directed toward the ultimate objective of mapping and surpassing all of human knowledge.The first chapter examines the theoretical foundations of the logical approach to artificial intelligence and the centrality of declarative knowledge and the predicate calculus. The artifical intelligence system, CYC, is critically examined with respect to its avowed objective of matching or surpassing human intelligence. The second chapter focuses on the probabilistic contrast model of causal reasoning and underscores its significance as a mathematical conceptualization of human reasoning. In the third chapter, the ARCS (Analogical Retrieval by Constraint Satisfaction) system is discussed and its psychological validity is evaluated. In the fourth chapter, scientific heuristics characteristics of different developmental levels and differentially applied in the discovery spaces of hypotheses and experiments are analyzed in the context of the philosophy of science. The fifth chapter presents the logic, principles, and applications of PAULINE, a pragmatic language generation system and explains human language pragmatics.