The concealed futility by the distinction between "utility" and "futility" is actually a kind of "utility", or even great serviceability, which is realized by mutual non-injury between the user and the substance to be used and display thorough performance of the two. The fundamental method for turning the "futility" into "utility" lies in "detachment" based on "de-subjectivation". Only by means of "detachment" can one reach the realm of leisure.