成唯識論演祕 2.408

2.408

難云：外法非趣、生，非趣生故無同分。外法非趣、生，非趣、生故無生等。若言外法是有為，外同內法有生等，亦應外法有相似，外同內法立同分，以古有宗外無同分，故為此難。

The objection says: External dharmas are not destinies or births; because they are not destinies or births, they have no generic similarity. External dharmas are not destinies or births; because they are not destinies or births, they have no arising, and so forth. If one says that external dharmas are conditioned, and external dharmas, like internal dharmas, have arising and so forth, then external dharmas should also have resemblance, and external dharmas, like internal dharmas, should establish generic similarity. Because the ancient Sarvāstivāda school held that external things lack generic similarity, this objection is raised.