Treating illness is the doctor's eight consciousnesses jointly transforming the patient's physical body.

When a doctor cures a patient's illness, does the doctor first change his own inner representation, or first change his own outer representation? How does the inner representation arise? If this question is not resolved well, one will be unable to attain enlightenment in the future. The question of whether the inner or outer representation comes first is extremely important; it cannot be bypassed, because it all involves the issue of the tathāgatagarbha manifesting all dharmas, and involves the questions of how the tathāgatagarbha manifests them and according to what it manifests them. Once this question is understood clearly, enlightenment becomes easy.

The patient is the doctor's outer representation. In treating the patient's illness, of course the patient's material body is changed, allowing the body to recover. The patient's material body is, to the doctor, an outer representation; treating the illness means that the doctor's own eight consciousnesses jointly change the patient's material body—that is, the doctor's outer representation is changed. The doctor's tathāgatagarbha transmits the outer representation through his own six faculties into the doctor's supreme faculty, where it becomes the inner representation, corresponding with the outer representation. The patient's material body seen by the doctor as the inner representation also recovers at the same time.

Treating an illness also requires the participation of the first six consciousnesses; all eight consciousnesses participate. If it is healing through contemplative visualization, the mind consciousness must also participate, with the sixth, seventh, and eighth consciousnesses jointly functioning to change the patient's material body. This is also a change in the patient who is the doctor's outer representation, and the patient's body in the doctor's inner representation changes at the same time. Exactly how the eight consciousnesses change the patient's material body, and how they function upon the material body of the outer representation, is something the Chan investigator must investigate; after breaking through the investigation, one will know.