Behaviorism and Cognitivism are two perspectives in cognitive science that have had significant impact in the evolution of mind theory. Behaviorism is centered in the study of mind from the perspective of externalized behavior. Behaviorism is opposed to the approach to mind analysis from an introspective point of view, even rejecting the existence of internal states. The cognitivist reaction explained some aspects of memory and learning that behaviorism failed to account for. Internal mental states –beliefs, values, intentions- are the common trade of cognitivist models. Cognitivism employs computer-based information processing as the paradigmatic principle sustaining cognitive modeling, where data structures implement the required internal mental states. These two approaches to cognitive science are usually considered as antagonistic; but they are not. The only difference is that they approach the problem of the modeling of mind from an input/output perspective or from a state-based perspective. Behaviorism focuses on using a black box model of minds while cognitivism focuses on white box models. Both are right and complementary approaches and are degenerate forms of a more fundamental approach that may be applied to mind modeling: systems identification.