More deliberate efforts have been witnessed recently that incorporate philosophical criticism and analysis in the exploration and clarification of current concerns in adult education. Such studies might be regarded as pioneering attempts at doing philosophical research in adult education. Philosophical research has a prominent role to play in redressing the impoverishment that preoccupation with narrowly conceived operational definitions has brought to the field. Methods of philosophical inquiry can alert adult educators to crucial limitations in statistical studies, raise questions about unconditional acceptance of operational definitions, and help examine the relevance of various research methods for adult education. Two prominent approaches to doing philosophy--linguistic/conceptual analysis and penomenology--are rigorous research activities with implications for adult education research. There is a vital task for linguistic analysis in examining and assessing the feasibility of leading concepts and norms. The outstanding theme of penomenological research, intentionality, opens the way for more penetrating philosophical investigations of self-directed learning. Other adult education issues which lend themselves to the descriptive research of these two philosophical approaches are ethical problems, such as mandatory continuing education and development of theory. (YLB)