Churchman’s five Inquiring Systems are considered in the light of Polanyi’s distinction between Tacit Knowing and Practical Thinking. It is suggested that the five Inquiring Systems are distinct and crucial elements of the Learning Organization that can be divided into two perspectives: the modes of Tacit Knowing and the levels of Practical Thinking. Tacit Knowing critically contributes to the sustainable growth of an organization through its connection with (1) intuition (2) holism, and (3) ethics.