The potentials and problems presented by the thesis of philosophy and their relationship to educational research and practice are discussed. The question of whether philosophy can have a unique thesis is examined. It is suggested that the thesis of philosophy asserts the creation of meaning as an ongoing project that must be constantly monitored. Divergent approaches to this thesis are illustrated in the work of H. G. Gadamer and J. Derrida. The most obvious way in which the thesis of philosophy bears on educational research and practice is that educators are deeply involved in the study of meaning. The field of testing provides an example of a fundamental way in which philosophy's thesis can improve educational research and practice. Learning could become motivated by the teacher and the learner's own curiosity; testing could become a matter of investigating the inquiry that is constitutive of learning with that constitutive of measurement. The author suggests that Rasch's measurement model is in tune with the thesis of philosophy. A 54-item list of references is included. (SLD)