瑜伽論記 14.419

14.419

次對六辨差別中，由三自性者，色等五塵不出三性，善、惡、無記，色聲，有是業性，故有作用，香味觸性非是業，皆無作用。

Next, in distinguishing differences in contrast to the six [sense objects], regarding "due to the three intrinsic natures": the five sense objects—form and the rest—do not go beyond the three natures: wholesome, unwholesome, and indeterminate. Form and sound have the nature of action (karma), and therefore have function; the natures of odor, taste, and tangibles are not action, and all lack function.