The purpose of this article is to draw educational implications by comparing and examining the infiniteness of Cantor, especially the practical concept and the denial of Wonhyo, that is, the indeterminate concept. Cantor presented the transfinite number that can be treated as a closed system like a number, away from the potential infinite concept that has been going on since Aristotle, and based on this, it presented the concept of practical limit based on the size comparison in infinity. Here, an unresolved paradox of continuum hypothesis occurs, which is called Cantor's paradox, which cantor failed to solve and eventually continued his unhappy life. In contrast, Wonhyo also faced an infinite problem, a paradox, but he concluded it as a ‘negative’ of ‘indetermination’ and lived a life of positivity. This fundamental difference should be seen as the fact that his logic based on his ‘One mind’, which thoroughly carried out the area of intuition in the face of the limitations of inferential thought, worked, and this is differentiated from Cantor. Through this comparative study, this study tried to suggest the meaning of inferential thinking in educational sense and intuitive thinking to supplement it.