The purpose of this thesis is to diagnose and cure some of the sources of conceptual confusion in psychology. Both the concepts of creativity and insanity are used as examples of areas of concern to psychologists. Wittgenstein (1958, 1969) suggests that in psychology theory and research are directed from confused conceptions of language resulting in a paralysis of understanding. It is by following Wittgenstein's articulation of the nature of philosophy, and by understanding the relationship between philosophy and psychology, that it is possible to disentangle the conceptual confusion and gain access to accurate theorising about insanity, creativity, and the relationship between the two phenomena. Cognitive science is criticised for perpetuating a mythology from which research is directed. Cognitive psychology relies on a misguided understanding of the nature of psychological predicates. Wittgenstein's arguments against the thoughts embodied in the cognitivist doctrine are used to disable this attempt to account for psychological concepts generally and provide a background to address the errors contained within computational accounts of creativity. Social constructionists claim that they accurately represent the introduction of Wittgensteinian philosophy into psychology. There are several attempts made by constructionists to criticise cognitive science and present alternative research programmes for psychology. It is argued that social constructionists fail to present a convincing argument against cognitivism and furthermore misinterpret Wittgenstein's philosophy and so fail to introduce Wittgenstein's thoughts to psychology. Theorising from a constructionist perspective about the concept of insanity is used as an example to expose the types of error which result from misinterpreting Wittgenstein's arguments. It is by contrast with these broad theoretical structures (both cognitive science and social constructionism) that the proper grammatical structure, at least from a Wittgensteinian perspective, for the concepts of insanity and creativity is developed. The relationship between grammar and evidence is explained against the background of argument in psychology relating to the study of creativity and insanity. Theoretical psychology is distinguished from philosophy with the recognition that philosophy provides conceptual clarification and psychology is involved with conceptual development. The relationship between empirical psychology and theoretical psychology is described in contrast to the relationship between philosophy and theoretical psychology. By describing Wittgenstein's conception of philosophy it is argued that Wittgenstein offered psychologists a resource which operates either to remove conceptual confusion or promote an overview to facilitate the correct employment of terms within theory.