成唯識論述記 5.597

5.597

述曰：此答也。謂此無明勝遍三性位，餘識無此遍三性心之無明，故名為不共。非在自有，餘識所無，名不共等。

The Commentary states: This is the answer. It means that this ignorance excels in pervading the states of the three natures, whereas the other consciousnesses lack this ignorance that pervades thoughts of the three natures; therefore it is called unshared. It is not called unshared merely by existing in oneself while being absent in other consciousnesses.