The philosophy of accreditation is discussed in a paper commissioned by the North Central Association of Colleges and Schools for a project on "Rethinking Accreditation." After defining accreditation and distinguishing it from assessment, evaluation and "meta-evaluation" are discussed, including the nature of accreditation in general, the importance of goals as norms of evaluation, and the importance of evaluating accrediting associations. Under the topic of epistemology and method, evaluation theory and methodology in accreditation are discussed in terms of public standards, institutional self-study, site visits by a visiting team, and the process of reviewing the team report with final confirmation by the commission. Two recurrent issues in this evaluation are the goal of helping improve the quality of the educational institution and the lack of a measure of outcomes independent of the evaluation process. The importance of the improvement of the quality of higher education is stressed. (SM)