The Commentary to the sutta, the Papa~ncasuudanii, explains the words of the
sutta:
<One who is forgetful and does not clearly comprehend>, here this is the
explanation: a monk who proceeds by the method, <Experiencing citta, I shall
breathe in,> etc... although he makes the sign(nimitta) of the
in-and-outbreathing the object, is nevertheless called someone who
contemplates citta in citta, because the citta of that monk proceeds by
establishing sati and sampaja~n~na (pa~n~naa) with regard to the object.
Because there cannot be the development of mindfulness of breathing for
someone who is forgetful and without clear comprehension. That is why, by
experiencing the citta as object, (it is said) <on that occasion... a monk
dwells contemplating citta in citta>
The Commentary on the Satipatthana Sutta (the Papa~ncasuudanii, translated
by Ven. Soma) states that just as in the case of body and feelings, citta
should be contemplated in seven ways: as impermanent; as being subject to
dukkha; as anatta; by way of turning away from it and not by way of
delighting in it; by freeing himself of passion for it; with thoughts making
for cessation and not making for origination; and not by way of laying hold
of it, by by way of giving it up.
Nina: these contemplations refer to the stages of insight: in the course of
insight there is a clearer understanding of the three characteristics of
impermanence, dukkha and anatta, and hence there is a growing detachment
from conditioned dhammas. When citta appears pa~n~naa should see citta in
citta, not a self in citta. Citta knows an object, it does not last and it
is not self who knows an object.
Nina.