成唯識論述記 7.111

7.111

述曰：尋、伺與四受相應，初定意有樂故。然此師說尋、伺五無一向定義，以不言與苦欲界樂俱故，此即意識無苦師義。

The Commentary states: Vitarka and vicāra are associated with four feelings, because in the first dhyāna the mind possesses pleasure. However, according to this master, there is no absolute determination that vitarka and vicāra are five [feelings], because he does not say that they are accompanied by pain or the pleasure of the desire realm; this is the position of the master who holds that the manovijñāna lacks pain.