To elucidate the mutual issuance theory in the Neo-Confucian philosophy of Yi T’oegye 李退溪 (1501–1570) is the precise endeavor of this essay, in order to find out if it is still philosophically meaningful and applicable for contemporary interpretations of the world. Presupposing bipolarity of principle and material force, physical and conceptual prehension, or matter-energy and information, it argues that the process o f attunement of the world is completed by the mutual issuance of material force and principle, or matter-energy and information. Whitehead believed physical prehension is prior to conceptual prehension in the process of making a subjective aim of each event. This essay asserts that the process could happen by way of mutual conceptual and physical prehension, and that priority does not always belong to physical prehension, but either one of them can make it a priority to move forward, as seen in the mutual issuance theory of T’oegye’s Neo-Confucianism. Principle or information does not always just lure, but initiatively informs matter-energy in order to allow for a new, emerging event in the mutual issuance process.