OP: As of now, it has not been explained in terms of physical interaction or as an emergent phenomenon.
Consciousness is what knows what is felt. If you see, hear, feel, smell, or think something you know consciousness is present. If there is no consciousness nothing is felt or known. Consciousness arises due to the interaction of the 6 sense bases with the outside world.
If you do not have consciousness either one is dead or it is an inanimate object.
OP: Nibbana is also said to be 'unconditioned' phenomena, all that is made of Matter or contains Matter is 'conditioned'. If it is nothingness or emptiness, what is the underlying Physics?
Nibbana is where the rules that govern both material and mental phenomena breakdown. Conventional physics does not work with Nibbana.
The woking of Nibbana cannot be expressed in conventional language. E.g. say there was someone living in a 2D world. They will not know what up and down is. For a person who has experienced, the 3rd dimension will not be able to explain what he experienced to others in the 2D world. There will be no vocabulary or means to explain it.
OP: A blind, deaf, mute, senseless, touchless, everyone can get Nirvana but someone without consciousness cannot get Nirvana
If you have a defect or disability then one cannot get Nirvana. For this reason, they are not allowed to enter the order. There are cases some have gone blind during meditation Cakkhupala Thera, but blindness happed while true insight arose.
OP: After death the person remains conscious, so what is it that essentially transmutes?
A person does not remain conscious after death. What happens is that consciousness passes away in the dead body and arise in another being. In the case of animals, it will be eggs, embryo, etc.
OP: EDITED: After Nirvana the person remains conscious, so what is it that essentially transmutes?
What changes is how one perceives the 5 Aggregates and reacts to sensory stimuli.
Here, houselord, an untutored ordinary person who sees not the noble ones, unskilled in the
way of the noble ones, untrained in the way of the noble ones, who sees not the true individuals and is
unskilled in the way of the true individual,
untrained in the way of the true individual
—regards form as self, or self as possessing form, or form as in self, or self as in form;
—he lives obsessed by the notions, "I am form. Form is mine."
As he lives obsessed by these notions, that form changes and alters. With the change and alteration of
form, there arise in him, sorrow, lamentation, (physical) pain, (mental) displeasure and despair
(1) Here, houselord, the learned noble disciple, who sees the noble ones, skilled in the way of the
noble ones, trained in the way of the noble ones, who sees the true individuals and is skilled in the way of
the true individual, trained in the way of the true individual,
—does not regard form as self, nor self as possessing form, nor form as in self, nor self as in form;
—he does not live obsessed by the notions, "I am form. Form is mine."
As he lives not obsessed by these notions, that form changes and alters. With the change and alteration of form, there do not arise in him, sorrow, lamentation, (physical) pain, (mental) displeasure or
When the uninstructed ordinary person is touched by a painful bodily feeling, he sorrows, grieves,
laments, beats his breast and falls into confusion.
This is called an uninstructed ordinary person who has not risen up from the bottomless abyss, one who
has not gained solid ground.
But, bhikshus, when the instructed noble disciple is touched by a painful bodily feeling, he does not
sorrow, nor grieve, nor lament, nor weep, nor beat his breast, nor fall into confusion.
This is called an instructed ordinary person who has risen up from the bottomless abyss, one who has
gained solid ground