OP: Is Nibbana a state of mind or a dhamma?
In this answer, we find the definition of dhamma quoted as:
dhamma [Skt. dharma]:(1) Event; a phenomenon in and of itself; (2)
mental quality; (3) doctrine, teaching; (4) nibbāna. Also, principles
of behavior that human beings ought to follow so as to fit in with the
right natural order of things; qualities of mind they should develop
so as to realize the inherent quality of the mind in and of itself. By
extension, "Dhamma" (usu. capitalized) is used also to denote any
doctrine that teaches such things. Thus the Dhamma of the Buddha
denotes both his teachings and the direct experience of nibbāna, the
quality at which those teachings are aimed.
For the purpose of this answer, we will use the definition of dhamma as a thing or phenomena - any thing. It could be physical or mental or empty space or time or non-physical and non-mental, or a concept or a teaching - any thing.
In this answer, a sankhara is summarized as:
Sankharas are "co-doings," things that act in concert with other
things, or things that are made by a combination of other things. Ven.
Bodhi uses "formations" or "volitional formations" as his preferred
translation.
There are 3 uses of the term Sankhara in the scriptures:
- Second link in dependent origination - when ignorance and craving underlie our stream of consciousness, our volitional actions of body,
speech, and mind become forces with the capacity to produce results,
including "rebirth".
- The fourth of the five aggregates - volition regarding forms, sounds, smells, tastes, tactile objects, and ideas. Also covers all
factors of mind except feeling and perception.
- All conditioned and compounded things including mountains, fields, and forests; towns and cities; food and drink; jewelry, cars, and
computers.
The only thing which is unconditioned and uncompounded is Nibbana.
We can say a sankhara is a thing or phenomena that is compounded or conditioned.
Absolutely everything is compounded and conditioned, except Nibbana.
Your body, your mind, your thoughts, your consciousness, your states of mind, the five aggregates, the idea of the self, the Buddha's teachings as an idea of the mind, the luminous mind (pabhassara citta), empty space, time - they are all conditioned and/or compounded.
In the physics of cosmology today, we know that even empty space is expanding in the universe (and therefore conditioned), and from Einstein's theory of relativity, we know about time dilation - the phenomena which proves that time is conditioned. From quantum field theory, we have learned that empty space (vacuum) is never truly empty, so even empty space is compounded.
Everything that is conditioned, would arise, change and cease depending on other conditions - for example, when you read this sentence, thoughts about the concept of sankhara arise in your mind, then ceases. Your understanding or views regarding this concept would also change with time.
Compounded refers to things that are built up of other things. For e.g. your body is built up of bones, flesh, blood, bile, saliva, cells etc. However, through objectification-classification or reification (papañca), we perceive them as concrete objects, relative to us. For e.g., this is my body, that is not my body.
The three marks of existence state that:
- All conditioned and compounded things or phenomena are impermanent. (sabbe sankhara anicca)
- All conditioned and compounded things or phenomena are suffering. (sabbe sankhara dukkha)
- All things or phenomena are not-self. (sabbe dhamma anatta)
There is clearly a classification here separating phenomena or things (dhamma) into conditioned/ compounded and unconditioned / uncompounded. Everything is conditioned and/or compounded, except Nibbana. Everything is impermanent and suffering, except Nibbana. Absolutely everything is not-self (anatta), including Nibbana.
So what then is Nibbana? It's not conditioned, not compounded, not suffering, not impermanent, not arising, not ceasing and not changing. Also see this question. Ud 8.1 and Ud 8.3 support this.
Nibbana is also the highest bliss. This supported by Dhp 203 - 204. So, it's easy to think that it is a state of mind. But states of mind are conditioned, but Nibbana is not. So, how can Nibbana be the highest bliss?
From this question, we find the Buddha talking about "The All" from SN 35.23:
"Monks, I will teach you the All. Listen & pay close attention. I will
speak."
"As you say, lord," the monks responded.
The Blessed One said, "What is the All? Simply the eye & forms, ear &
sounds, nose & aromas, tongue & flavors, body & tactile sensations,
intellect & ideas. This, monks, is called the All. Anyone who would
say, 'Repudiating this All, I will describe another,' if questioned on
what exactly might be the grounds for his statement, would be unable
to explain, and furthermore, would be put to grief. Why? Because it
lies beyond range."
From this question, we concluded that Nibbana is included in The All. So, if Nibbana is not a state of mind, then it is a thing that can be experienced by the mind. But Nibbana is also not a thought or concept or feeling, because thoughts, concepts and feelings are also conditioned. Please see this answer. Neutral feelings, no feelings and Nibbana are all blissful to the arahat.
From AN 9.34 (translated by Bhikkhu Sujato):
Ven: Sariputta: “Reverends, extinguishment (Nibbana) is bliss!
“sukhamidaṃ, āvuso, nibbānaṃ.
Ven. Udayi: “But Reverend Sāriputta, what’s blissful about it, since nothing is
felt?”
“kiṃ panettha, āvuso sāriputta, sukhaṃ yadettha natthi vedayitan”ti?
Ven. Sariputta: “The fact that nothing is felt is precisely what’s blissful about it.
“Etadeva khvettha, āvuso, sukhaṃ yadettha natthi vedayitaṃ.
So, Nibbana is not a thought of the mind, not a concept of the mind, not a state of the mind, not a state of consciousness and also not a feeling. However, when the mind experiences this Nibbana, which is not conditioned, not compounded, not suffering, not impermanent, not arising, not ceasing and not changing, it experiences bliss. The mind can therefore experience Nibbana, but it cannot feel it or think about it.
Sukha or happiness for an unenlightened person is experienced when encountering pleasant feelings (from the six senses) or when encountering the cessation of painful feelings (from the six senses). But for an arahat, sukha or bliss (in this context) is experienced when encountering neutral feelings, no feelings and Nibbana. Please see this answer for commentaries by Nyanaponika Thera. The supporting suttas are MN 44, SN 36.5 and AN 9.34.
OP: how would a stream winner experience/see Nibbana with the existence of craving?
The stream winner glimpses Nibbana in moments when he is in perfect mindfulness (sati) and clear comprehension (sampajañña) of the four noble truths, the eightfold noble path, the three marks of existence and dependent origination, through wisdom and insight (vipassana). These are the moments when he understands things clearly as they truly are (yathābhūtaṃ pajānāti). These are moments when the five hindrances have been stilled and effluents (asava) are temporarily not arising, but ignorance (avijja) has not been completely uprooted yet. When the five hindrances are stilled and effluents are ceased, craving does not occur. See this answer for details on sati sampajañña.
When the stream winner is not in mindfulness (sati) and clear comprehension (sampajañña), he is afflicted by craving and suffering. However, since he has seen things clearly as they are, identity view, doubt about the teachings and attachment to rites and rules would have been uprooted completely. However, some of underlying tendencies (anusaya - see AN 7.11), especially craving and ignorance, still exist, hence the remaining fetters still exist.
OP: "One attain Nibbana by uprooting craving" or "One uproots craving by attaining Nibbana" Which one of the aforesaid is correct?
The answer given by Dhammadhatu based on SN 22.59 is the right one for this.