The Four Nutriments: what do the metaphors in SN 12.63 mean?

• Son's flesh - eating itself is unsatisfactory (as the sensations produced by it is unsatisfactory - Kīta,giri Sutta). eating should be only to maintain life to fulfil holy life and not for the please of it.
• Skinned cow - there is not place or way to avoid contact. With contact follows sensations [Paticca-samuppada-vibhanga Sutta, see Dependent Origination] which are unsatisfactory [Cūla Vedalla Sutta], hence it nibbles.
• Pit of glowing embers - all volitions are accompanied by sensations throughout the body. [121 mental states] Whatever sensations end in misery, thus burns. Also this is the fuels which drives you and burns you until death
• Robber's struck with spears - it is thought consciousness that you know and experience. If not for consciousness you will not feel sensations. [Dhātu Vibhaṅga Sutta] Being alive is like having consciousness. All sensation are unsatisfactory [Cūla Vedalla Sutta], hence the pain of been struck by spears.

Here's my personal interpretation of SN 12.63.

To understand each of the similes, the clue is in the epilogue of each simile. The nutriments are not taken literally. Each simile becomes harder to interpret than the previous one. Each simile is also related in some way to the previous simile.

First simile

The epilogue says "When the nutriment edible food is fully understood, lust for the five cords of sensual pleasure is fully understood." The five cords of sensual pleasure (MN13) are forms, sounds, aroma, flavours and tactile sensations.

The nutriment of edible food here is not literally edible food, but refers to the external sources of forms, sounds, aroma, flavours and tactile sensations.

The simile teaches us that these "edible food" should be used only as a means to get through samsara, while living the holy life, to reach the end of suffering, and one should not have passion for them.

The nutriment of the external sources of the five cords of sensual pleasure, nourish and sustain the five cords of sensual pleasure. Literal edible food is the source of flavours, for example.

Second simile

The epilogue says "When the nutriment contact is fully understood, the three kinds of feeling are fully understood." The three types of feeling (Iti 52) are pleasure, pain and neither-pleasure-nor-pain. There are six types of contacts (SN 12.2) - eye-contact, ear-contact, nose-contact, tongue-contact, body-contact and intellect-contact.

The cow is exposed to different environments like wall, tree, water, open air. These are like contacts. The creatures biting her are the three types of feeling. The biting itself is craving. The painful sensation that arises from the biting is suffering (from dependent origination: from feeling as a requisite condition comes craving; and from the second noble truth: the cause of suffering is craving).

The simile teaches us to abandon passion for the three types of feeling arising from contacts. The creatures (feeling) are fine, but don't let them bite you (craving). For the bite is painful (suffering). The nutriment of contacts nourish and sustain the three types of feeling.

To link back to the previous simile, SN 12.44 says for example, "dependent on the ear & sounds there arises ear-consciousness. The meeting of the three is contact". So, five types of contacts are directly related to the five cords of sensual pleasure. The sixth type of contact is indirectly related to the five cords of sensual pleasure.

Third simile

The epilogue says "When the nutriment mental volition is fully understood, the three kinds of craving are fully understood." The three types of craving (Iti 58) are craving for sensuality, craving for becoming and craving for non-becoming.

The word for "nutriment of mental volition" in this sutta is manosañcetanāhāro. From SN 12.38, we read: "what one intends, and what one plans, and whatever one has a tendency towards: this becomes a basis for the maintenance of consciousness." I interpret mental volition here as intention (cetana) and latent tendencies (anusaya).

SN 12.38 also says "If one does not intend, and one does not plan, but one still has a tendency towards something, this becomes a basis for the maintenance of consciousness", which shows latent tendencies are required for the maintenance of consciousness, even if intention isn't present. There are 7 types of latent tendencies in AN 7.11.

The two strong men are either latent tendencies (anusaya) or latent tendencies and intention (cetana). They grab the man and drag him towards the charcoal pit with glowing coals. The glowing coals are craving. If the man comes into contact with the glowing coals, the arising pain is suffering (from the second noble truth: the cause of suffering is craving).

The simile teaches us to abandon latent tendencies. Don't let the strong men (latent tendencies) drag you into the charcoal pit of glowing coals (craving). Run away from the strong men (latent tendencies). The coals are painful (suffering). The nutriment of latent tendencies nourish and sustain the three types of craving.

To link back to the previous simile, the three types of feeling will not result in the arising of craving, if there are no latent tendencies.

Fourth simile

The epilogue says "When the nutriment consciousness is fully understood, name-and-form is fully understood." Based on the definition of name-and-form in SN 12.2, name-and-form is a kind of mind-body link (according to Theravada interpretation).

And what is consciousness? From dependent origination: from consciousness as a requisite condition comes name-and-form. From the traditional Theravada interpretation of consciousness in dependent origination, this is the consciousness that results in the continuity of suffering beyond physical death, called "rebirth linking consciousness" (cuti citta) in the Abhidhamma.

This is supported by SN 12.39: "When consciousness is established and has come to growth, there is a descent of name-and-form", and SN 12.38: "When consciousness is established and has come to growth, there is the production of future renewed existence." When the suttas talk about the growth, increase, maturing, landing and establishing of consciousness, it essentially talks about consciousness resulting in the descent of name-and-form ("rebirth").

In dependent origination, craving leads to clinging, which leads to becoming. These show the outflow of effluents or mental fermentations or taints (asava), which according to this "cyclic" question causes the arising of ignorance. Then ignorance in turn causes the arising of effluents once again (MN 9), which is mental formations (sankhara) including latent tendencies (anusaya). This then causes the arising of consciousness, which causes the descent of name-and-form (mind-body link) i.e. "rebirth".

This loop back from craving-clinging-becoming back to ignorance is hinted at, in SN 44.9: "when a being sets this body aside and is not yet reborn in another body, I designate it as craving-sustained, for craving is its sustenance at that time."

The bandit or criminal is the one who delights in craving, the fool from SN 12.19, who clings (steals). The king could be ignorance or samsara. The king's men who strike him with spears are mental formations (especially latent tendencies). The spears are (rebirth linking) consciousness. The striking of the spears is the descent of name-and-form (that is "rebirth"). The pain caused by the striking of spears is suffering (birth, aging, death, sorrow, lamentation, pain, distress and despair). Morning, afternoon and evening could be different aeons.

Wouldn't three hundred lifetimes be painful? Well, even one lifetime is painful enough, don't you find from experience? The simile teaches us to abandon stealing (craving), in order to not get struck ("rebirth") by spears (renewed "rebirth linking consciousness") again.

This is reinforced in the Tears Sutta (SN 15.3):

From an inconstruable beginning comes transmigration. A beginning point is not evident, though beings hindered by ignorance and fettered by craving are transmigrating & wandering on. Long have you thus experienced stress, experienced pain, experienced loss, swelling the cemeteries — enough to become disenchanted with all fabricated things, enough to become dispassionate, enough to be released."

The nutriment of (rebirth linking) consciousness nourishes and sustains the (descent of) name-and-form.

To link back to the previous simile, the three types of craving (plus clinging and becoming) are the effluents that cause ignorance, and ignorance causes effluents (latent tendencies especially) in turn, that causes (rebirth linking) consciousness to rise again, causing the descent of name-and-form ("rebirth").

Case of arahants

How does this apply to the case of arahants?

From Thanissaro Bhikkhu's commentary of Iti 44:

With fuel remaining (sa-upadisesa) and with no fuel remaining (anupadisesa): The analogy here is to a fire. In the first case, the flames are out, but the embers are still glowing. In the second, the fire is so thoroughly out that the embers have grown cold. The "fuel" here is the five aggregates. While the arahant is still alive, he/she still experiences the five aggregates, but they do not burn with the fires of passion, aversion, or delusion. When the arahant passes away, there is no longer any experience of aggregates here or anywhere else.

A living arahant experiences the nutriment of edible food and the nutriment of contacts, but he has ended the nutriment of mental volition (i.e. latent tendencies) and therefore also ended the nutriment of (rebirth linking) consciousness. Then, consciousness has no place to land or get established any more (SN 12.64) i.e. no more descent of name-and-form (SN 12.39) meaning no more continuity of suffering after physical death. After parinibbana, all nutriments would have ceased permanently.

Conclusion

The sutta is talking about dependent origination, what keeps dependent origination going, how to end dependent origination, and the truth of the continuity of suffering beyond physical death.

It is true then that the noble eightfold path does not just lead to the cessation of (craving for) form, but also the cessation of (the rearising of) form. (see this question)

Existence is nourished by four nutriments as pointed out in the Sutta in @Dhammadhatu ‘s OP. They are essential to continue life in this repeated existence in samsara. This is true even to the deities in the celestial world and brahmas in the Brahma world. Of these four kinds, one is material/physical, and the other three are mental nutriments. The first is the easy one as @Dhammadhatu pointed out. But how can one see one’s mental state or mental growth if not for the guidance that the Buddha provided in many of the suttas? The Buddha provided the explanation in the Atthi Raga Sutta (where there is passion) in the Samyutta Nikaya.

How we have to view the four similes is that ONLY if we eradicate the Cause, would the Result be eradicated, and NOT otherwise. It is our Desire for Life that prevents this. The day that we establish wisdom over ignorance, and liberation over desire, we will see the light. The day we remove our passion, delight and craving for the four nutriments Consciousness will not arise. Then mentality-materiality won’t happen, and as a result there is no growth of fabrications, and no renewed becoming. If no future birth, there is no decay, death, sorrow, lamentation, pain, grief and despair.

To explain the 2nd simile - that of the nutriment sense-impression:
Sense impression (phassa ahara) is Contact. So what is contact? It is the coming together of three things. It is the eye, the visible object and consciousness coming in contact with each other (seeing forms). It is the ear, sounds and consciousness coming in contact with each other (hearing sound). it is the nose, odours and consciousness coming in contact with each other (smelling odours), and likewise. What is important to understand is with the arising of consciousness, it is inevitable for contact to arise. Only if we eradicate the desire for what we see, hear, smell, taste, touch and think, will the contact and consciousness not arise. The simile of the flayed cow is about this contact that one cannot get away from as long as there is desire.

To explain the 3rd simile - that of the nutriment volitional thought:
Volitional thought (Cetana) is Intellectual Intention. It is the arising of wholesome or unwholesome intentions. As before, these mental factors are a result of desire. Beings who cannot comprehend that these mental factors are not permanent, that they constantly change, and be mindful, gets thrown into the pit whether they like it or not. Only getaway is eradicating the cause – the arising of ‘cetana’ – of intellectual intention.

To explain the 4th simile - that of the nutriment of Consciousness:
Our sense faculties are constantly contacted and stimulated because of Consciousness as explained before. The two that I did not touch on are that of the body and intellect. Dependent on the body and tactile sensations, arises consciousness at the body. Dependent on the intellect (ideas/thoughts), there arises consciousness at the intellect. With the Consciousness, desire arises. This arising of passion, delight and craving results in greed, hatred and delusion – these are the spears that one gets shot at with. As long as you have passion, delight and craving, you are alive and get shot at and experiences pain and distress.

So our Desire for the Dhamma, to live in the Dhamma should be even greater than our desire for Life. Those are the ones who will stay in the finger tip. What the Buddha has said is patisotagami or against the current of conventional thinking. Buddha knew this well. That is why He said,

“Dear Bhikkhus, ones who would not realize this Dhamma is like this earth (in amount). Ones who realize this is like this small amount of soil on my finger nail.”

Its simple, i will explain each 4 nutriement in points

(1) physical food- it is to be regarded only for survival ,not for flavour or intoxication. We should treat our physical food like we are feeding on our young baby

(2) contact- if contact happens with our six senses (eye, ear, skin ,etc) to its corresponding object (vision, touch etc) then that object chew on it.. for example if you have eye and lets say its corresponding object is p**nography.. then we should regard p**nography as something chewing our eye.. ultimately destroying it...but since we normally dont question our sense-object , we enjoy it till our ruin.

(3) volition- buddha said you should regard volition as survival instinct only.... here a man hates death.. but a practitioner sholuld not fear death... so he is saying normally we have volition that act upon survival instinct..we dont act truly but act according to survival instinct

(4) consciousness- well , if u are ever depressed, tensed and wanted to end your life ,,you should know its all because of your damn consciousness...so consciousness is spear acting upon us..buddha is saying to take this consciousness in command

Finally, what he meant is that the above 4 food is necessary for survival. . If you cant survive then how will you attain nirvana...but he is saying dont take these food unmindfully..see what game is undergoing behind the scene..in 1 word right view ...right view about these food is necessary for salvation ..hope it helps. If any question please ask. Glory to Buddha

While the sutta did not state the nutriments are evil, it did give vivid and explicit similes of the son's flesh, the skinned cow, the man being dragged toward a burning pit, and a criminal being pierced with three hundred spears. Needless to say, one doesn't have to be very smart to think carefully before indulging oneself with the nutriments after hearing what the Buddha just said. Imho, SN 12.63 reflects the Dukkha inherent in all conditioned phenomena. And the Four Nutriments are no exception. For us regular worldlings, we tend to only understand the 1st of the 3 aspects of Dukkha, Dukkha-dukkha, for the obvious reason that it's right there in front of our naked eye. That's why we continue to indulge in the nutriments and sense pleasures. It would take a significant degree of cultivation and penetrative insight to understand the other 2: Viparinama-dukkha and Sankhara-dukkha. And until then, we'd still only be able to have some superficial understanding of what SN 12.63 was trying to say. Per ChrisW's suggestion, I've reposted as an answer and include the 2 very helpful links from Prof. Tan and Ven. Nyanaponika with detailed commentary on SN 12.63:
http://www.themindingcentre.org/dharmafarer/wp-content/uploads/2009/12/20.6-Puttamamsa-S-s12.63-piya.pdf
http://www.accesstoinsight.org/lib/authors/nyanaponika/wheel105.html

The Four Nutriments ('ahara') of physical food, sense contact, intention & consciousness are true for the worldlings who have craving (tanha) and greed (lobha) or aversion / revulsion (dosa), caused by ignorance (moha). Tanha, lobha, dosa, moha provides nourishment for the continuation of life from existence to existence.

The worldlings have five aggregates of clinging (Panca Upadana Khandas). In the case of Arahants – the awakened ones - there is no craving. They have rooted out the “I concept”. They have fully realized five groups of existence and the five grasping groups of existence (Panncakkhandha and panca upadanakkhandha) . Arahants have only the five aggregates in detachment (Anupadana). Upadana means ‘grasping’ and Anupadana means ‘non-grasping’ or letting go.While Upadana leads to Samsara, Anupadana leads to Nibbana.

To put it in another way, (for better understanding), after the elimination of all defilements an arahant lives in society without Upadana or Attachment to any thing in the world. He does not have the five grasping groups (pancaupadanakkhandha) but only five groups,aggregates (Pancakkhandha), namely, rupa (body), vedana (feeling), sanna (perception), sankhara (volitional formation), and vinnana (consciousness). His consciousness is ‘translucent’ (for wont of a better word) as no food is provided. In this he is immeasurable - is like the Buddha. All measurement is from a here to a there, with in-betweens. In the Buddha, there is neither a here nor a there nor any in-between. He is thus immeasurable. See Bahiya Sutta: About Bahiya - Ud 1.10

“Then, Bahiya, you should train yourself thus: In reference to the seen, there will be only the seen. In reference to the heard, only the heard. In reference to the sensed, only the sensed. In reference to the cognized, only the cognized. That is how you should train yourself. When for you there will be only the seen in reference to the seen, only the heard in reference to the heard, only the sensed in reference to the sensed, only the cognized in reference to the cognized, then, Bahiya, there’s no you in that. When there’s no you in that, there’s no you there. When there’s no you there, you are neither here nor yonder nor between the two. This, just this, is the end of stress.” (Ud I.l0)...

An arahant is sustained by ONLY the physical food that does not create upadana. He does not have the other three ‘mental’ foods as he has rooted out the “I concept”. He is free from attavada upadana by seeing it as a deceit (the true nature). So if there is no nutriment consciousness, an Arahants consciousness is mere presence. Since there cannot be presence without something being present, it is what distinguishes living from non-living, such as tables and chairs. The Buddha has stated that consciousness is dependently arisen, since without a condition there is no origination of consciousness. In an Arahant, Paticcasamuppada (dependent arising) ceases. Which means Vinnana paccaya (conditioned by consciousness) too ceases.