This essay examines types of overlapping thought between subjects. The definition of "interdisciplinarity" that is proposed is a thought process that overlaps subjects. It is oriented toward a topic as a whole, leading to standardization of the comprehension of phenomena by connecting partial explanations of different sciences with one another. The task of interdisciplinary research is not to be solved with a global interdisciplinary theory. It must be pursued within individual sciences in daily usage, and must entail attention to problems of language and clarifying the core questions. Theory should nurture practice, effecting a gradual change that promotes attention to questions that border on individuals' areas of specialization.