As the bridge of entering Happy Excursion, the book On Seeing Things as Equal points out the origin of closure of human hearts──intentionality.? In the comparisons of natural music in the first paragraph, he proclaims the forms of the music of man, land and heaven.? The music refers to the hollow soul of true hearts close to dao, which is the original appearance of men.? In the accomplishments realm, it is in opposition to music of land and music of heaven in waiting.? The mental realm by evidence of music of heaven makes chaotic of all confrontations in happy excursion without waiting.? With slowly disappearing of intentionality and clearing up of compositions of falseness of minds, the realm of principal body is enhanced level by level from the mang wei of waiting to happy excursion of music of heaven without waiting to show the truth of life.? The true mastering of the foundation, i.e., dao in our life, not only penetrates music of the three as the foundation of accomplishments.? When peeling off other involved evidence of music of heaven realm, it is equal to nature of dao realm, which is the philosophy of principles and implications of music of nature.