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if the mind is not paying attention, how can it discern subtle Truth (such as 4NT, DO, 3Cs, etc)?

dear Esho, Dhamma friends & fellow Truth Seekers

the teaching is very simple. there is no need to complicate it. it simply means the practitioner gives attention to Dhamma (Truth)

here is a suitable unambiguous quote:

So ajjhattaṃ suññataṃ manasi karoti. Tassa ajjhattaṃ suññataṃ manasikaroto suññatāya cittaṃ na pakkhandati nappasīdati na santiṭṭhati na vimuccati . Evaṃ santametaṃ, ānanda, bhikkhu evaṃ pajānāti – ‘ajjhattaṃ suññataṃ kho me manasikaroto ajjhattaṃ suññatāya cittaṃ na pakkhandati nappasīdati na santiṭṭhati na vimuccatī’ti. Itiha tattha sampajāno hoti.

He attends [gives attention] to internal emptiness. While he is attending to internal emptiness, his mind does not take pleasure, find satisfaction, grow steady or indulge in internal emptiness. When this is the case, he discerns, 'While I am attending to internal emptiness, my mind does not take pleasure, find satisfaction, grow steady or indulge in internal emptiness.' In this way he is alert [has clear comprehension] there.

MN 122

He then attends to internal emptiness. While he is attending to internal emptiness, his mind takes pleasure, finds satisfaction, grows steady & indulges in internal emptiness. When this is the case, he discerns, 'While I am attending to internal emptiness, my mind takes pleasure, finds satisfaction, grows steady & indulges in internal emptiness.' In this way he is alert there.

He attends to external emptiness...

He attends to internal & external emptiness...

He attends to the imperturbable. While he is attending to the imperturbable, his mind takes pleasure, finds satisfaction, grows steady & indulges in the imperturbable. When this is the case, he discerns, 'While I am attending to the imperturbable, my mind takes pleasure, finds satisfaction, grows steady & indulges in the imperturbable.' In this way he is alert there.