成唯識論述記 7.645

7.645

述曰：第三簡略，如此中說，展轉相望亦非因緣，既言異類，不能親生俱或異時異類果故。

The Commentary states: This is the third qualification. As stated here, in mutual relation they are also not cause-conditions, for since they are called 'heterogeneous', they cannot directly produce simultaneous or temporally distinct heterogeneous results.