From "A Lamp For The Path To Full Awakening By Lama Atisha"

Discriminating Intelligence (Prajna)
Being aware of the emptiness of natural existence, which involves the realization that the aggregates, sensory spheres and bases are not created, is the full explanation of what constitutes "wisdom". It is impossible for existent entities to be created and also non-existence is like a flower in the sky. Since fallacies consequently will be present for either, both together can never arise.
Things are not created from themselves, nor from others, nor from both, nor from no cause. Therefore, essentially they have no nature in themselves.
Furthermore, when one analyses all phenomena as unitary or multiple, being essentially un-apprehensible (as such), one will ascertain that they lack any nature of their own. The reasons in such texts as (Nargarjuna's) 'Seventy Emptiness's' and his 'Fundamental Treatise on the Middle Way' show that the nature of all things is established as being empty. Because this text would become too extensive, I will not elaborate any further here. I just mention it to establish my tenets and to explain it properly for meditation.
Thus the nature of every single phenomenon is un-apprehensible. Whatever constitutes the meditation on non-self existence is the meditation of discriminating intelligence. Just as discriminating intelligence does not see any nature in all phenomena, mentally analyze that intelligence itself (and) meditate on that without any conceptualizing. As worldly existence arises from conceptualization, it is itself a conceptual thought. Therefore, the discarding of every conceptualization is the supreme state beyond sorrow.
Furthermore, Buddha the Endowed Destroyer has similarly stated:

"Conceptualization, the great ignorance, throws one into the ocean of cyclic existence.
Dwell in non-conceptualizing meditative concentration, clear, without concepts, like space."

Also he has said in the 'Mystic Recitation of Engaging in Non-conceptualization:'

"O Son of the Conqueror, in this high practice of Dharma, if one contemplates non-conceptually on appearance,
one will transcend the difficult to pass conceptions and gradually will come to non-conceptuality."

Once you have attained through such scriptural sources and reasoning that phenomena - by lacking a nature of their own - in their entirety are uncreated, meditate without conceptualizing.

The Spiritual Paths And Levels