The character 悟 (GO, sato(ru)) means “enlightenment; to perceive, discern, realize, understand.”
Notice how 悟 contains the heart radical, , called 立心偏 (risshinben: to stand + heart + left-side radical). Even though this kanji relates to perception, it involves the heart, not the eye (目). As Antoine de Saint-Exupéry wrote in The Little Prince, “It is only with the heart that one can see rightly; what is essential is invisible to the eye.”
And, oh! I just discovered that 覚 and 悟 combine in a word: 覚悟 (kakugo: readiness, resolution, to perceive + to become aware of).