The citta arising at the first moment of life must also have a function. What is
birth, and what is it actually that is born? We speak about the birth of a
child, but in fact, there are only nāma and rūpa which are born. The word
'birth' is a conventional term. We should consider what birth really is. Nāma
and rūpa arise and fall away all the time and thus there is birth and death of
nāma and rūpa all the time. In order to understand what causes birth we
should know what conditions the nāma and rūpa which arise at the first
moment of a new lifespan.
What arises first at the beginning of our life, nāma or rūpa? At any moment
of our life there have to be both nāma and rūpa. In the planes of existence
where there are five khandhas (four nāmakkhandhas and one rūpakkhandha),
nāma cannot arise without rūpa; citta cannot arise without the body. What is
true for any moment of our life is also true for the first moment of our life. At
the first moment of our life nāma and rūpa have to arise at the same time.
The citta which arises at that moment is called the rebirth-consciousness
or patisandhi-citta. Since there isn't any citta which arises without
conditions, the patisandhi-citta must also have conditions. The patisandhi-
citta is the first citta of a new life and thus its cause can only be in the past.
One may have doubts about past lives, but how can people be so different if
there were not past lives? We can see that people are born with different
accumulations. Can we explain the character of a child by the parents? What
we mean by 'character' is actually nāma. Could parents transfer to another
being nāma which falls away as soon as it has arisen? There must be other
factors which are the condition for a child's character. Cittas which arise and
fall away succeed one another and thus each citta conditions the next one.
The last citta of the previous life (dying-consciousness) was succeeded by the
first citta of this life. That is why tendencies one had in the past can continue
by way of accumulation from one citta to the next one and from past lives to
the present life. Since people accumulated different tendencies in past lives
they are born with different tendencies and inclinations.