Dear Pali friends,
(I am especially delighted to meet Nina van Gorkom),

I would like to discuss with you a hypothesis about the meaning of
the term 'nimitta' in jhana.

First, the various meanings of this word (Ekamipata-Atthakatha 1.32):

Subhanimittanti raaga.t.thaaniya.m aaramma.na.m. "Sanimittaa,
bhikkhave, uppajjanti paapakaa akusalaa dhammaa, no animittaa"ti ettha
nimittanti paccayassa naama.m. "Adhicittamanuyuttena, bhikkhave,
bhikkhunaa pa~nca nimittaani kaalena kaala.m manasikaatabbaanii"ti
(ma. ni. 1.216) ettha kaara.nassa. "So ta.m nimitta.m aasevati
bhaavetii"ti (a. ni. 9.35) ettha samaadhissa. "Ya.m nimitta.m aagamma
ya.m nimitta.m manasikaroto anantaraa aasavaana.m khayo hotii"ti (a. ni.
6.27) ettha vipassanaaya. Idha pana raaga.t.thaaniyo
i.t.thaaramma.nadhammo "subhanimittan"ti adhippeto.

Here the maenings of 'nimitta' are:
- paccaya;
- kaara.na;
- samaadhi;
- vipassana;
- nimitta of the attractive as a basis for passion and desire.

The abovementioned sutta AN 9.35
http://www.accesstoinsight.org/canon/anguttara/an09-035.html
tells that each jhana has a nimitta. In order to master the jhana
monk "sticks with that theme [nimitta], develops it, pursues
it, & establishes himself firmly in it".

As nimitta of the attractive is the basis for passion, so the nimitta
of absence of attractiveness (asubhanimitta) is a kamma.t.thaana
(basis of meditative practice).

In the context of samaadhi nimitta has a synonym - sa~n~naa. The words
asubhanimitta, asubhasa~n~na, aniccanimitta, aniccasa~n~na are
interchangeable.

But what is a nature of nimitta in the context of samadhi?
A passage in Sangiti sutta (DN 33, Ro: 3.261) (also in MN 77)
describes the stages of kasina practice:

"A.t.tha abhibhaayatanaani. Ajjhatta.m ruupasa~n~nii eko bahiddhaa
ruupaani passati parittaani suva.n.nadubba.n.naani, 'taani abhibhuyya
jaanaami passaamii'ti eva.msa~n~nii hoti. Ida.m pa.thama.m
abhibhaayatana.m.

"Ajjhatta.m ruupasa~n~nii eko bahiddhaa ruupaani passati appamaa.naani
suva.n.na dubba.n.naani, 'taani abhibhuyya jaanaami passaamii'ti-
eva.msa~n~nii hoti. Ida.m dutiya.m abhibhaayatana.m.

"Ajjhatta.m aruupasa~n~nii eko bahiddhaa ruupaani passati parittaani
suva.n.nadu bba.n.naani, 'taani abhibhuyya jaanaami passaamii'ti
eva.msa~n~nii hoti. Ida.m tatiya.m abhibhaayatana.m.

"Ajjhatta.m aruupasa~n~nii eko bahiddhaa ruupaani passati
appamaa.naani suva.n.nadubba.n.naani, 'taani abhibhuyya jaanaami
passaamii'ti eva.msa~n~nii hoti. Ida.m catuttha.m abhibhaayatana.m.

"Ajjhatta.m aruupasa~n~nii eko bahiddhaa ruupaani passati niilaani
niilava.n.naani niilanidassanaani niilanibhaasaani. Seyyathaapi naama
umaapuppha.m niila.m niila va.n.na.m niilanidassana.m niilanibhaasa.m,
seyyathaa vaa pana ta.m vattha.m baaraa.naseyyaka.m
ubhatobhaagavima.t.tha.m niila.m niilava.n.na.m niilanida ssana.m
niilanibhaasa.m. Evameva ajjhatta.m aruupasa~n~nii eko bahiddhaa
ruupaani passati niilaani niilava.n.naani niilanidassanaani
niilanibhaasaani, 'taani abhibhuyya jaanaami passaamii'ti
eva.msa~n~nii hoti. Ida.m pa~ncama.m abhibhaaya- tana.m.

http://www.metta.lk/tipitaka/2Sutta-Pitaka/2Majjhima-Nikaya/Majjhima2/077-mahasakuludayi-e1.htm

A certain one with internal material perceptions*1) sees limited
external forms beautiful and ugly. Mastering them says, I know and
see. This is the first mastery.

A certain one with internal material perceptions sees unlimited
external forms beautiful and ugly. Mastering them says, I know and
see. This is the second mastery.

A certain one with internal immaterial perceptions sees limited
external forms beautiful and ugly..Mastering them says, I know and
see. This is the third mastery.

A certain one with internal immaterial perceptions sees unlimited
external forms beautiful and ugly. Mastering them says, I know and
see. This is the fourth mastery.

A certain one with internal immaterial perceptions sees blue forms
with the colour, hue and lustre. The colour of blue lotuses, with hue
and lustre beaten in, like kashmire cloth, with the colour hue and
lustre beaten in, on both sides. Mastering them says, I know and see.
This is the fifth mastery.

-----------

Note the expression 'aruupasa~n~nii'. First the disciple perceives the
kasina with his physical senses (ruupa). On the next stage he perceives it
with immaterial apperception.

Comparing this description with the kasina practice as described in
Vimuttimagga and Visuddhimagga, I came to conclusion that 'nimitta'
means exactly this 'aruupasa~n~naa', i.e. immaterial (extrasensory)
apperception of the concentration object.

I would appreciate any opinions and comments about this hypothesis.

Metta,
Dimitry