Sentience, killing, & extremes?

• What determines an animal's sentience?

What determines a being:

From the Pali words: pana, pāṇāni:

• Something that breaths (excluding plants). Also see: What is Prana according to Buddhism?

From Definition of Dependent Origination of Satta

• Something that has consciousness
• Something that has the 5 aggregates or Name and Form in full or in part (In asaññasatta - Unconscious beings - wold there is no sanna, and arupa-loka - The Immaterial World - there is no rupa, with these exceptions in other worlds all 5 aggregates must be present)
• Something that has the 6 sense bases in full or in part
• Something that feels
• Something that perceives

From Abhidhamma:

• Something that has the life faculty (Jivitindriya)

All being are sentient as when their faculties make contact they feel and perceive. So what determines sentience is if one is a being.

...

Source: P51 - 52, Pāli Buddhism By Hoffman Frank

Mr Suminda here expressed well what is included in sentience.

The working out of the exact results of action & intention is not to be done, as far as i know.

The consequent origination is without a discernable beginning and the exact results of this or that action is not something that is easy to figure out.

There is no forumulae or a solver which can simulate two beginningless worlds, arrive at the same states of the world and split the desicion tree to compare outcomes; that would not be possible because if two systems evolve in exact same way with an infinite complexity then it is unreasonable to expect the decision tree to split in and by itself, as a matter of fact there is no decision tree either because world just evolves, it does not stop to think should i go this way or that way, become this or otherwise; it goes according to prior development.

However even if there was a decision tree there is no basis for a split if values are exact and same given that the systems simulate the same exact premises and conditions. This is not like simulating a move in chess or blackjack because these games have determined starting points and a "decision maker".

Therefore one can not evaluate actions in this way, there is no way to input values and simulate outcomes for action A comparing to action B, having solved for which one could say that 'one is better than the other because the better one has exactly this much estimated shorter time to Parinibbana'.

Therefore the exact values are difficult to work out. There are other circumstances where this comes into place, like the Parajika of stealing; "A bhikkhu must have stolen a certain amount for the circumstance to be considered an offence of defeat". Figuring out these values in their exacts & particulars is impossible at this point afaik.

Nothing else makes sense, the type of thinking; 'If i get maggots i will have found my assasin', is going to lead to inconsistencies and reveal hipocrisy imo. This is because a person who says he will be devoured by worms rather than break his training, he is saying "lives of others are sacred, i can train even as i am devoured by worms", but at the same time this same person probably goes for walks to exercize his legs where he might step on an animal, drives a car that might kill even a group of people or he causes others to walk and drive even if it is for his training or the training of others, so why sacrifice beings when it is better to train even when devoured by worms?

It is going to be inconsistent because there is no way to say this life-form goes and this one's are ok to hit with a car on a way to make living or the supermarket. There are all sorts of problems with that thinking, it seems like a person like this would want to sit down and not break the sitting posture until arahantship and then go without food but maybe that is not an option as it might kill the bacteria, beings and worms currently in the body.

There's discussion between Buddhists of different schools about whether it's important to have a vegetarian diet.

• Some say "yes" -- because eating meat involves farming and killing or hunting animals -- and even if you don't kill them yourself, your paying for meat contributes to that industry and cycle.

• Some (as you probably know) say "no" -- that it's alright to buy already-dead meat in a market provided the animal wasn't killed specifically for you. They'd also point out that vegetarians too contribute to killing animals -- that ploughing the soil kills worms, that harvesting grain may kill mice, and so on.

  The proper reaction to that, I've seen it argued, is samvega and so on.

Anyway, I wonder whether killing a parasite like a tape-worm (by taking medicine) for the health of "my" body is morally similar to killing an earth-worm by digging in "my" garden to grow food.

I think that Jains are a little more extreme about "harmlessness" than Buddhists -- and that they view fasting to death as ethical -- which as you might point out is not the Middle Way of Buddhism.

I'm not sure what the rule would be for Buddhist monks. Perhaps they're expected to be obedient in taking medical prescriptions when they're ill. I don't know in fact whether a monk or doctor who prescribes a medicine would avoid prescribing a medicine which would kill a parasite (or other infection). I think that a medicine which "purges" is one of the traditional types of medicine according to the Vinaya.