I initially thought that it is because there’s no mindfulness in bhavaṅga, but then I checked, and mindfulness is in the universal good cetasikas and to be reborn as humans we would have them in our bhavaṅgas. So what’s the deal with mindfulness being there in bhavaṅga and we are not aware of it?
Here is a reply by Nina van Gorkom:
Re: Abhidhamma Studies part 2 - rise and fall of cittas, vibhanga comy
Question:> What about Bhavanga that occurs between two cittas?
> What happens when one enters in a coma or complete cessation of
> perception and feeling, etc. Then there would be a gap between two
> normal states of consciousness.
> --------
Nina: In between processes of cittas that experience objects through the
six doors, there are bhavangacittas arising and falling away.
Quote from Survey of Paramattha dhammas:
<> Kamma not only produces the rebirth-consciousness asresult. When the rebirth-consciousness has fallen away,
kamma also conditions the arising of the succeeding citta
which is the same type of vip�kacitta and performs the
function of bhavanga, life-continuum. As we have seen, this
type of citta maintains the continuation in the life span of
someone as a particular person until death. So long as the
dying-consciousness has not arisen yet the bhavanga-cittas
that arise and fall away perform the function of preserving
the continuity in one�s life. They perform their function at the
moments there is no seeing, hearing, smelling, tasting, the
experiencing of tangible object or thinking. Thus, the rebirth-
consciousness, the bhavanga-citta and the dying-
consciousness are cittas that do not arise in processes; they
are not v�thi-cittas.
When we are fast asleep, we do not see or experience
other sense objects, we do not think. The bhavanga-cittas
arise and fall away in succession all the time, until we dream
or wake up, and there is again seeing, hearing, the
experience of other sense objects or thinking of different
subjects of this world. This world does not appear to the
rebirth-consciousness, the bhavanga-citta and the dying-
consciousness. At the moment the vip�kacitta arises and
performs the function of rebirth or the function of bhavanga,
the different objects of this world, in our case the human
world, do not appear. If we would be fast asleep at this
moment, we would not know anything, we would not see
anyone who is here.
We would not experience sound, odour, cold or heat. The
bhavanga-citta is not involved with anything in this world. It
does not even know who we are, where we are, who are our
relatives and friends. It does not know anything about
possessions, rank, an honourable position, happiness or
misery. Whereas when we are not asleep we remember the
things of this world, the different people and the different
stories connected with this world.
When we see, there is no bhavanga-citta, but v�thi-citta
instead, which arises and sees what appears through the eyes. >
> Nina: We cannot experience the object of bhavangacitta, it is the same
> object as experienced by the rebirth-consciousness. Bhavangacitta
> itself can be experienced, but this depends on the developed insight.
> Why not study what you can experience right now, like seeing or
> visible object? Then you can understand more the nature of citta. We
> do not have to think of trillions of citta, that is just thinking. It
> is best just to attend to what appears right now.
Nina.
If the bhavanga citta cannot be experienced, it means that it simply cannot be remembered (since memory is taking the past citta as an object of the present citta). Why can’t the bhavanga citta be taken as an object/remembered? What is it about its properties that prohibits this? Why does the fact that the bhavanga citta takes the deathbed vision and the sign of kamma make it unfit for remembering?