Originally posted by PedoBear:so intent is important?
if i got into a car accident and killed alot of people unintentionally, i am not accumulating bad karma?
so the belief is that we should not kill sentient being only and not all life?
cos i thought the teaching is not to 'sha shen' (literal translation kill life)
if that is true, then buddhist consider cows, chickens, fishes etc sentient?
Cows, chickens, fishes are sentient (conscious) beings. They suffer. Grass, plants, are alive but they do not have consciousness, discrimination, mind, and suffering. Hence they are edible.
As for your other question, hope this helps:
Extract from 'Only We can Help Ourselves' by Dhammavuddho Thero.
Kamma-vipaka is sometimes translated as cause and effect ('yin kuo' in Chinese books) but that is not a good translation.
This is because there are two types of cause and effect - worldly cause and effect, and kammic cause and effect.
The difference can be seen, for example, when you drive a car and suddenly a small boy runs across the road, and you hit the boy and kill him.
You did not have have the intention to kill the small boy, so you did not create any kamma. However you did knock down the boy and the boy's family might pull you out of the car when you stop, and beat you up. In addition to that, they might also sue you in court.
So there is a result of knocking down the boy, namely, you get a beating and then be sued in court. However this is worldly cause and effect. It is not concerned with Buddhist kamma vipaka because there was no intention on your part to kill the boy.
So we must clearly differentiate between worldly cause and effect and kamma-vipaka. They are different because one involves action with intention and the other does not.
...The working of kamma-vipaka is very complex. The Buddha said in one discourse (Anguttara Nikaya 4.77 - Acintita Sutta / 增一 阿�經，分别功德论�第一) that there are four things that you should not think about too much. If you think too much about these four things, you could become deranged.
The first is the power of the Buddha;
The second is the depth and power of jhana (meditative absorption);
The third is kamma-vipaka;
And the fourth is speculation about the world.
...The working of kamma-vipaka depends not only on our present lifetime but also on many, many lifetimes of unsettled kamma accounts.
On top of that, it also depends on the state of our mind at that moment. Moreover, the state of mind of the other being you do the kamma to also affects your vipaka.
For example, when you make an offering to a murderer, or a criminal, or to an evil person, your merit is very small, but if you make an offering to a holy man, then your merit or blessings is great. Conversely, if you kill a holy man, then your kammic offence is very great. If you kill a mosquito, the kamma is not as bad, but still you are not encouraged to kill it.
...Sometimes we see certain people whom we consider as evil, rough, stingy and offensive, but they are having a good, luxurious life. That could be due to their good kamma from past life supporting them. However they are now creating a lot of evil kamma which has not ripened yet. This could be due to the fact that people can change.
For example, when a man is poor he is humble, industrious, faithful to his wife, frugal, etc. When he becomes rich after several years, he may become arrogant, vain, womanize, drink, gamble, etc. - a completely different personality.
Similarly, a good person in a previous life, when reborn under favourable conditions, might become corrupted by his good fortune. Because of this we may find it hard to see fairness in this world.
Sometimes we see that good people are not the ones who are happy, but many evil people are happy.
The working of kamma-vipaka is very difficult to see unless we have the psychic power to look into the past.