成唯識論述記 6.175

6.175

述曰：因中五識或有、或無，無此時多，有此時少。第六意識有此時多，無此時少。

The Commentary states: In the causal stage, the five consciousnesses may or may not possess them: they are absent most of the time and present only rarely. The sixth mental consciousness possesses them most of the time, and lacks them only rarely.