http://dharmafarer.org/wordpress/wp-content/uploads/2010/02/31.3-Anusaya.-piya.pdf
An essay written by Piya Tan, taken from his website http://dharmafarer.org/wordpress/
i remember there's a thread recently regarding morality in the
Noble Eightfold Path, here's a quote from the essay which might
provide another understanding.
1.5 LEVELS OF DEFILEMENTS. Although all defilements are, in
a sense, anusay, the seven mentioned
here are the most prominent (Abhs:BRS 268).43 The first three
latent tendencies (of sensual lust, of
aversion, and of conceit) are mentioned in the Sall’atthena Sutta
(S 36.6)44 and the Ca,vedalla Sutta
(M 44), the latter of which says: “The latent tendency of sensual
desire underlies pleasant feeling. The
latent tendency of aversion underlies painful feeling. The latent
tendency of ignorance underlies a neutral
feeling” (M 44.25/1:303). The Majjhima k on this passage says
that these three defilements are called
“latent tendencies” in the sense that they have not been destroyed
in the life-continuum (bhav’aga) to
which they belong and because they are capable of arising when the
conditions are right (MA:Be 2:286).
The Visuddhi,magga explains how this happens by distinguishing
three levels of defilements, that is,
as follows:
(1) The transgression level (vtikamma), a gross level of
defilements, where they instigate unwholesome
bodily and verbal action.
(2) The obsession level (pariyuhna), an obsessive level of
defilements, where they arise to obsess
and enslave the mind.45
(3) The latent level (anusaya), a subtle level of defilements,
where they remain as latent disposition
in the life-continuum (bhavaga).
We had already mentioned the compound adhihnbhinivesnusaya,46
translated as “the latent
tendencies of mental standpoints and adherences” [1.2]. They are
“mental standpoints” (adhihna)because they are the foundations
for the unwholesome mind, and “adherence and latent tendencies”
because
they adhere to the mind and lie latent there (SA 2:259; NmA
2:310).
Evidently, this compound embodies the canonical roots for the
commentarial conception of the three
levels of defilement. The “mindset” or “mental standpoint”
(adhihna) here refers to the motivation behind
the gross level of transgressive defilement. “Adherence or
habituation” (abhinivesa) refers to the
motivation behind the habitual level of addictive or obsessive
defilement. The “latent tendencies” (anusay
) lie dormant in the life-continuum (bhav’aga), ready to rear
their ugly heads and wreak havoc at the
slightest instigation.47
The gross level of transgressive defilement is prevented by the
observance of moral precepts (sla).
The habitual level of obsessive defilement is surmounted through
mental cultivation (samdhi). And the
subtle level of latent defilement is overcome by insight wisdom
(pa) (Vism 1.13/5). These three levels
of defilements are often referred to throughout the
Commentaries.48