The Conditions for the Arising of the Mental Factor of Mental Engagement (Manaskāra)

Answer: The manas' mental engagement is not only triggered by afflictive mental factors such as greed and hatred, but also relies on being triggered by the mental factor of desire (chanda). Desire includes wholesome desire and unwholesome desire, as well as desire that is neither wholesome nor unwholesome. Wholesome desire is the power of great vows; unwholesome desire is greed, hatred, and delusion. Part of the manas' mental engagement is also habitual mental engagement, brought about by the force of inertia.

 Original text in the Yogācārabhūmi-śāstra: 云何能生作意正起﹖由四因故﹕一由欲力。二由念力。三由境界力。四由数习力。云何由欲力﹖谓若于是处心有爱著﹐心则于彼多作意生。云何由念力﹖谓若于彼，已善取其相，已极作想﹐心则于彼多作意生。云何由境界力﹖谓若彼境界或极广大﹐或极可意正现在前﹐心则于彼多作意生。云何由数习力﹖谓若于彼境界﹐已极串习﹐已极谙悉﹐心即于彼多作意生。若异此者﹐应于一所缘境，唯一作意﹐一切时生。

These are the conditions for the arising of the mental factor of mental engagement (manaskāra): desire, mindfulness, sense objects, and habituation. That is to say, without desire and mindfulness, mental engagement cannot occur. In particular, it is the manas' desire and mindfulness: only after the manas engages mentally can the six consciousnesses arise, and only then can the six consciousnesses engage mentally.

If you wish to cultivate meditation, you must control and change the manas' habitual mental engagement and subdue its grasping tendency. The grasping tendency also refers to the manas' habitual mental engagement. Whether or not karmic seeds ripen has no necessary connection with the manas' mental engagement. Whether or not karmic seeds ripen, the tathāgatagarbha naturally comes to know it, and then the tathāgatagarbha begins to produce certain conditions, operating the corresponding dharmas in accordance with the karmic seeds.