Can Buddhist Practitioners Use Non-Buddhist Methods?

The so-called non-Buddhist (tīrthika) teachings refer to teachings that do not belong to the tathāgatagarbha—teachings expounded apart from the mind of the tathāgatagarbha are called non-Buddhist teachings. Many non-Buddhist teachings are of great use to Buddhist practitioners, so do not reject useful non-Buddhist teachings. When a doctor treats a patient, that too is a non-Buddhist method. Can we abandon non-Buddhist methods and rely solely on the tathāgatagarbha teaching to resolve everything? Clearly not. Non-Buddhists eat, and we must eat as well; non-Buddhists live on this earth, and we cannot leave the earth either; non-Buddhists breathe air, and we likewise breathe the same air. Since beginningless kalpas, we have never been apart from non-Buddhist teachings, and after taking up Buddhism we still need to cultivate teachings that are the same as those of non-Buddhists—this is necessary. Apart from lacking the teaching of the tathāgatagarbha and the teaching of the non-self of the five aggregates (pañca-skandha), non-Buddhists possess all other teachings, and we must also be complete in them. For example, the non-Buddhists' sense of renunciation, their aspiration for liberation, their meditative concentration (samādhi), and their various methods for resolving problems of the physical body are all well worth our learning; as long as they are useful to us, we should use them. In fact, all non-Buddhist teachings are tathāgatagarbha teachings. Even when a doctor cures a patient's illness, it is the tathāgatagarbha that cures it—in essence it is still the tathāgatagarbha teaching. No person or teaching can be separated from the tathāgatagarbha; all are produced by the tathāgatagarbha, and their essence is the tathāgatagarbha.