The paper has tried to examine the meaning of the differentiation of mind regarded as ``educatedness``. There are two main aspects of the differentiation of mind: the logical aspect of school subjects and the psychological aspect of mind. As already argued, the two are to be integrated for the progressing feature of mind development. Though, a problem arises from the process of this integration which cannot restrict to the articulated domain of the content. Ryle`s knowing-how, Hayek`s muddling, and Polanyi`s tacit knowing respectively throw light on the significance of non-articulated domain of human knowledge, both in the epistemological and educational contexts. The non-artificial meaning of common sense has also been taken into account. The tacit dimension takes part in the process in which children as well as scientists try to inquire their own topics and plays an important role for recognizing things and formating relevant concepts for them, which Polanyi has demonstrated this in his Tacit Dimension. This would require so-called ``academic freedom`` for the better state of human knowledge. For this the progressivsts and romantists indeed tend to reject the tradition for the these inquiries, which for Polanyi is a detrimental mistake. Whether or not we recognize the articulation of educational content, we never fail to accept the tradition for the growth of understanding and the development of mind in order to be educated in terms of the differentiation of mind.