T’oegye(退溪, 1501-1570) dedicated the Mujin six provisions
memorial to the Throne to SunCho(宣祖) in 1568(Mujin:戊辰).
This memorial to the Throne clearly shows the meaning of the
sage learning, and we can find T’oegye’s view of it before
publishing the Ten Diagrams on Sage Learning(聖學十圖) in it.
He thought the sage learning is based on the passage “the
mind of man is restless, its affinity to what is right is small.
Watch carefully and practice hard, that you may sincerely hold
fast the Mean.(人心惟危, 道心惟微. 惟精惟一, 允執厥中.)”
“Investigation of things” and “perfection of knowledge” in the
Greate Learning and “understanding what is good” in the
Doctrine of the Mean are ways of “watching carefully”, and
“making the will sincere”, “rectification of the mind” and
“cultivating the personal life” in The Greate Learning and
“being sincere with oneself” in the Doctrine of the Mean are
means of “practicing hard”. If one becomes a man who has
real knowledge of the highest good through “the perfection of
knowledge” and practices the knowledge of that through
“practicing with effort”, we call him a sage who knows our
own nature and practices it. While the goal of the natural
science is recognizing the object, the sage learning aims at
knowing and practicing our own nature. Thus, natural scientists
and sage learners have different views on aims and methods of
their study. If we come to understand this distinction, it might
be a great contribution to the complementary convergence of
these two fields of study.