Hi Alexi,
What the Buddha said in the Mahaparinibbana sutta shows that it is possible to be conscious and awake and yet not of the external five sense world. And secondly, it is something the Buddha himself engages in and practice. And three, it is deeper than the ones where one can still perceive external senses. Also the Pamsudhovaka Sutta shows that a samadhi where we can still think about the dhamma during meditation is not full tranquility.
" there still remain thoughts about the dhamma (dhamma vitakka). That samadhi is not yet peaceful and sublime; it has not attained to full tranquillity , nor has it achieved mental unification (ekodibhava) ; it is maintained by strenuous suppression of the defilements . –Pamsudhovaka Sutta
The two suttas shows that thinking or reflecting on the dhamma while in meditation is not full serenity, also the Buddha goes beyond the senses while fully conscious and awake in meditation. It is possible and it is not discouraged.
Dmytro wrote: "The "letting go" Brahmavamso talks about is slipping without any resistance into the passion for "beautiful representation" (subha-nimitta)."
There various types of sign mentioned in the sutta. When Ajahn Brahmavamso speaks about the sign which he describes as beautiful he is referring to the sign of the mind . Although the subha nimitta mentioned is translated as the sign of the beautiful , it is not the same one which he describes as beautiful. There are certain types of nimitta the Buddha suggests we focus on and certain ones he suggest that we don't . Below are a few examples :
1. Cittassa nimitta : sign of the mind ( this is the one Ajahn Brahm is refering to ,a " mental sign", ) - FOCUS
" only a beautiful MENTAL SIGN , a nimitta, remains. This pure MENTAL OBJECT "- A. Brahm
" The eyes are closed, and the sight consciousness has long been turned off. it is the mind consciousness freed for the first time from the world of the five senses. ....It is the mind ( citta ) manifesting- it is not a light, but for most it appears as a light. it is perceived as a light because this imperfect description is the best that perception can offer. "- Ajahn Brahm
2. Subha-nimittam: a beautiful object ( that we see in the external physical world) - NOT FOCUS
3. Asubha-nimittam: repulsive object. - FOCUS
4. Patigha Nimittam : an repugnance object ( that we see in the external physical world) . Patigha: repulsion, anger, repugnance . - NOT FOCUS
5. Samadhi nimitta: Samadhi sign ( this corresponds to the Samadhi Indriya of the Five Spiritual Faculties / Indriya instead of an object that we either see in the 5 sense world or within ) - FOCUS
6. Paggaha nimitta: the Effort sign ( this corresponds to the Effort Indriya of the Five Spiritual Faculties / Indriya instead of an object that we either see in the 5 sense world or within - FOCUS
7. Upekkha nimitta: the Equanimity sign- FOCUS
1.Cittassa nimitta
" there are cases where a foolish, inexperienced, unskillful bhikkhus dwelled focused on the body in & of itself -- ardent, alert, & mindful -- putting aside greed & distress with reference (related) to the world. While he dwelled focused on the body in & of itself, his mind does not become concentrated, his defilements ( the five Hindrances) are not abandoned. He does not pick up that SIGN. He dwelled focused on feelings in & of themselves ... the mind in & of itself ... mental qualities in & of themselves -- ardent, alert, & mindful -- putting aside greed & distress with reference (related) to the world. While he dwelled focused on mental qualities in & of themselves, his mind does not become concentrated, his defilements ( 5 hindrances) are not abandoned. He does not pick up that SIGN. As a result, he does not gain pleasant abiding in this very life, nor does he gain mindfulness & alertness. Why is that? Because the foolish, inexperienced, unskillful bhikkhu does not pick up the SIGN of his own mind (CITTASSA NIMITTA) .
The wise bhikkhu picks up the SIGN (NIMITTAM) of his own mind (cittassa):
"In the same way, there are cases where a wise, experienced, skillful monk dwelled focused on the body in & of itself -- ardent, alert, & mindful -- putting aside greed & distress with reference (related) to the world. While he dwelled focused on the body in & of itself, his mind becomes concentrated, his defilements ( the five Hindrances) are abandoned. He picks up that SIGN (NIMITTA) .
"He dwelled focused on feelings in & of themselves ... the mind in & of itself ... mental qualities in & of themselves -- ardent, alert, & mindful -- putting aside greed & distress with reference (related) to the world. While he dwelled focused on mental qualities in & of themselves, his mind becomes concentrated, his defilements ( 5 hindrances) are abandoned. He picks up that SIGN (NIMITTA).
"As a result, he gain pleasant abiding in this very life, together with mindfulness & alertness. Why is that? Because the wise, experienced, skillful monk picks up on the SIGN (NIMITTA) of his own mind (cittassa)."- Suda Sutta
2. Subha-nimittam
“Bhikkhus, I do not know of any other thing that leads to the arising of unarisen sensual desire and increases the development of arisen sensual desire than the sign of beauty ( subha-nimittam, a beautiful object) . Improperly attending to (ayoniso manasi karoto) the sign of beauty arouses non-arisen sensual desires and increases the development of arisen sensual desires. This is the first.
3. Asubha-nimittam
"Bhikkhus, I do not know of of any other thing more conducive to the non arising of sensual desires that have not arise and the fading of arisen sensual desires than the sign of repulsiveness (asubha-nimittam) . Properly attending to (yoniso manasi karoto) the sign of repulsiveness, bhikkhus, leads to the non-arising of sensual desire that haven't arise and the fading of arisen sensual desire. --Nivaranappahana Vagga ( AN 1.11- 1.20 )
4. Patigha Nimittam
“Bhikkhus, I do not know of any other thing that leads to the arising of unarisen aversion and increases the development of arisen aversion than the sign of aversion ( patigha-nimittam, patigha: repulsion, anger, repugnance) . Improperly attending to (ayoniso manasi karoto) the sign of aversion arouses non-arisen aversion and increases the development of arisen aversion. ----Nivaranappahana Vagga ( AN 1.11- 1.20 )
5 -7 Samadhi nimitta, Paggaha nimitta and Upekkha nimitta
Bhikshus, when a monk is devoted in [engaged in] the higher mind, from time to time, three signs should be attended to. (1) The concentration sign (samādhi,nimitta) should from time to time be attended to. (2) The effort sign (paggaha,nimitta) should from time to time be attended to. (3) The equanimity sign (upekkhā,nimitta) should from time to time be attended.
Bhikshus, if a monk devoted to the higher mind were only to attend to the concentration sign, it is possible that it would bring about laziness . Bhikshus, if a monk engaged in the higher mind were only to attend to the effort sign, it is possible that it would bring about restlessness . Bhikshus, if a monk engaged in the higher mind were only to attend to the equanimity sign, it is possible that it would not bring the mind to the full concentration [right samadhi] for the sake of destroying the mental influxes.
Bhikshus, insofar as a monk, devoted to the higher mind, only from time to time attends to the concentration sign, only from time to time attends to the effort sign, only from time to time attends to the equanimity sign, to that extent, the mind, pliant, malleable and bright, uncorrupted, it would fully concentrate for the ending of the influxes.
With metta,