Philosophy is the crystallization of human wisdom, which though highly abstract, originates from, conforms to, and works on reality. Epistemology, methodology, and theory of practice are interconnected philosophical propositions. Epistemology indicates the theoretical premise of methodology and theory of practice; methodology gives technical guidance for translating epistemology into theory of practice; and theory of practice, in turn, modifies and improves epistemology and methodology. Any think tank problem invariably reflects the mutual influence and advancement of epistemology, methodology, and theory of practice. Based on the internal intellectual logic of development, this chapter deals with the basic issues of think tank science and engineering with respect to epistemology, methodology, and theory of practice. It clarifies the fundamental connotations of the relevant core concepts from a philosophical perspective, the law of discipline development, and the basic scope and development trends of think tank research, providing philosophical and theoretical support for the development of think tank science and engineering.