The Principle of the Interpenetration of the Six Sense Faculties

For example, when everyone is looking at the text on a phone screen, at the same time the mind can know what the content means, and the hand can touch the screen to turn the page, knowing where one has read up to and that the screen should be swiped, and then thoughts arise in the mind, and one cannot help typing a question. Clearly it is only the eyes that are looking at the text, yet the other faculties can coordinate with one another, producing a whole series of activities. This shows that when one faculty moves, all six faculties can move.

Why can all six faculties move? Behind them there must be something in common that unifies the six faculties together. Although they are six distinct faculties, in essence they are still one, with no difference. Therefore, when one cultivates to a certain degree, the six faculties can interpenetrate and be used interchangeably, without distinction or obstruction.

The World-Honored One said in the fifth volume of the Śūraṅgama Sūtra: （六根）在毕竟同中，生毕竟异。This means that the essence of the six faculties was originally one, with no difference; however, because sentient beings, throughout beginningless kalpas, have failed to guard their own nature and have desired to seek outward, within a single faculty the six distinct faculties have arisen. If through cultivation one unties and dissolves away all the six faculties, then in the end not a single faculty remains—everything is the true suchness self-nature (tathatā-svabhāva), with not the slightest other dharma. In this way, sentient beings abide in the original state, return to their self-nature, and no longer transmigrate.