Who makes the worst Bad Kamma:
One who knows or one who does not know?

M: I was reading The Questions of King Milinda[1] edited by NKG Mendis and came across a question on which I would like some clarification:
Pg 68 Question no 25: Doing Evil Unknowingly:
King Milinda said: "Reverend Nagasena, for whom is the greater demerit: he who does an evil deed knowingly or he who does an evil deed unknowingly?"
"His is the greater demerit, sire, who does an evil deed unknowingly."
"Well then, revered sir, do we doubly punish any of our family or our court who does an evil deed unknowingly?"
"What do you think about this, sire? If a man should unknowingly take hold of a red-hot ball of iron, glowing with heat, and another should take hold of it knowingly, which would be more severely burnt?"
"He who took hold of it unknowingly, sire, would be more severely burnt."
"Even so, sire, the greater demerit is this who does an evil deed unknowingly"
"You are dexterous, revered Nagasena."
In the above example, he who took unknowingly would indeed be burnt more severely.
As I see it, unknowingly here is used in the sense "without knowledge that the ball is hot" rather than "without intention to hold." Intention is clearly there but the knowledge that the ball is hot is absent.
Wouldn't it be more appropriate the other way around in other kammas? I mean, when I know that 5 precepts laid down for the lay people are evil and I still indulge in them shouldn't my result be more severe than someone who doesn't know that they are evil?
For example, Muslims are required by their religion to slaughter animals in a prescribed manner for their consumption if they cannot buy halal (as it is called) meat in the market. So shouldn't their result be less severe as compared to someone who kills animals for pleasure?
I don't know how appropriate is it to give an example of other religion but laws of dhamma are the same for people of all the religions.
To deal with the last issue first: Here, where we are trying to investigate the truth of things it is appropriate to compare the Buddha's Dhamma with any perceived truth out there. We are not trying to impose our conclusions on anyone else. And, of course if we arrive at a conclusion that we can reasonably think will cause conflict with another group, there is no need to bring it up unasked.
On King Milinda's question:
I would have answered: Great King! Imagine a still calm pool of clear water. Then imagine tossing a stone into that water. Would there be ripples?
There would be ripples.
In fact, there would be no way to act on that water without disturbing the molecules at least on some level.
The amount of Disturbance the observer would see in that water would depend on three factors:
The Force with which the Disturbance was Created;
The Mechanism used for Creating that Disturbance; and
the Attributes of the Boundaries of the Pond.
A large stone, Thrown with violent force, into a shallow small pond would not produce the same observed disturbance as would a small stone, slipped gently into the water of a large pond.
And in both these cases the disturbance would be the same whether the person doing the throwing was unknowning of the mechanisms or not, is that not the case?
In the same way, The Kamma, the rebound [the force] of an intentional act of body, word-thought-and-speech, or mind, depends on the power of the actor, the power of the deed, and the power of the recipient of the deed.
The Power of an individual is proportional to the objective detachment of the individual [An individual who is not completely detached is holding bias in a certain direction; holding bias in one direction is maintaining opposition to the forces of the other direction; maintaining opposition to forces of any sort diminishes Power. -- You might think of the recipient as being either hard surfaced or sponge like: the rebound off the hard surfaced individual (one who had no clinging or bias) would be greater than that of the sponge like individual (one who had clinging or bias)]; Deeds assume their importance to the degree which they conduce to objective detachment. And these factors are at work whether the individual is aware of it or not.
The Subjective Experience of a kammic rebound (whether it is felt as pleasant, unpleasant, or neither pleasant nor unpleasant) depends on the intent with which the deed was done. One intends to do an act which causes pain; one intends to do an act which causes pleasure; or one intends to do an act which brings kamma to an end; this intent can originate with the individual or with another individual; (and there are acts which are mixtures of intent).
This allows for the possibility that the consequences of a forceful bad act done by a weak individual with intent to cause harm to a powerful individual could be experienced at a later time, by that same individual who has made himself powerful, as an insignificant unpleasant sensation (as well as other variations).
Therefore on many grounds neither is Milinda's question nor is Nagasana's answer well formed.
For instance, Nagasana's example may in fact be wrong. It may be that an individual, knowing that the coals are hot panics and actually grips the coal more tightly than would be advised while the individual ignorant of the condition might well act instinctively and with greater speed.
Kamma is not a one-dimensional law.
In your example we would need to know much more to give a proper answer. Suppose more of the variables were equal. Suppose the two men were equally situated in all ways except that the one was familiar with and approved of the idea of kamma and the other was ignorant of the concept. Both have the intent to inflict harm on the goat. The deed is the same; the goat will not suffer less because one man is aware of kamma and the other is not. But in the case of the man who is aware of kamma, the possibility exists that insight occurs subsequent to the deed and in time for compensatory measures to be taken (for example, building up a great storehouse of good kamma, or, the Buddhist solution: to so cultivate the mind as to have escaped kamma altogether as in the state of being Arahatta -- kamma manifests it's consequences in body, sense experience, perception, in what is perceived as "one's own", and in consciousness; if none of these things are perceived as "The Self" or "One's Own" then one has escaped the kammic rebound).[2] In this case, he who was unknowing suffers more. . . but not as a result of the kamma of the original act, but because of subsequent kamma.
But Nagasana's statement: "His is the greater demerit, sire, who does an evil deed unknowingly" implies that this is the case in every case and that is not an aspect of Kamma. He has, as you suggest, apparently mixed together the concepts of knowledge and intent.
Again, we have the case of a man intending to provide a meal to further the life of a powerful individual. But unknown to this individual, the meal has become contaminated by food poisoning. Here, because the intent was to cause good, the kammic rebound is not only not bad, but will have a good outcome. (If the powerful man is ignorant and assumes harmful intent and punishes his benefactor, the punishment experienced by the food giver must be attributed to a previous act of bad kamma, not this good deed).
But take the same case with the added factor that the individual involved is ignorant of the workings of kamma and he might well experience remorse and regret and grieve and lament and in other ways inflict pain on himself. Not only will his remorse and so forth be experienced as pain, but because he has inflicted these things on himself he creates additional bad kamma!
On the King's part, he assumes too much (as do most kings) in assuming the role of the force of kamma in suggesting he doubly punish unknowing offenders, and will only effectively be doubling his own bad kamma (unknowingly I presume) -- as you pointed out: kamma is a force of nature, it is not a matter of beliefs or laws. Kamma is a matter between the individual and himself: it is initiated by one's own acts and is experienced by one's self alone in accordance with the variety of factors just discussed.
V: In the above, in the situation of the case of a man intending to provide a meal to further the life of a powerful individual. But unknown to this individual, the meal has become contaminated by food poisoning, with the added factor that the individual involved is ignorant of the workings of Kamma and experiences remorse and regret and grieves and laments and in other ways inflicts pain on himself. Is it to be understood that in order for a person to avoid additional bad Kamma, one should not feel bad for doing bad, once having done a bad deed?
Take the example of three people who go fishing.
Person A has no idea that when he puts the worm on the hook (injuring and potentially killing the worm) that this act is bad Kamma or that when he hooks the fish and kills it, this is also bad kamma.
Person B is aware that when he hooks the worm, catches and kills the fish, this is bad kamma, but feels no remorse.
Person C is aware that when he hooks the worm, catches and kills the fish, this is bad kamma, but does feel remorse.
Which individual has the worst accumulation of bad kamma coming to him?
In your example A (as unlikely as this would be) if he had no idea, that this act was causing injury or death (say, imagining that the worm was rubber?), then he would not even experience the bad kamma from killing the worm.
In Case B (again, highly unlikely, except in the case of the psychopath), he experiences the bad kamma from killing the worm but none from inflicting the pain and discomfort of remorce on himself. (Frankly, I seriously doubt even the psychopath really avoids remorse; it just takes a form unrecognized by the rest of us; perhaps displaced in time...time served, that is, in Niraya.)
In case C he experiences the bad kamma from killing the worm and also from inflicting remorce on himself.
Just to anticipate: he "inflicts remorce" on himself by knowingly acting in a harmful way, knowing he will feel remorse therafter. My point in drawing a distinction between the bad kamma from an injurious act and the bad kamma from the remorse is not to suggest that there is a way to cause deliberate injury and slip passed without a care, it is to point out the unnecessary suffering inflicted on one's self when one assumes unwarranted guilt. The advantage, for one who knows that remorse is a separate and distinct instance of bad kamma is in the ability to make use of its presence to act quickly to learn the act that caused it and to immediately train one's self to abstain from such a thing in the future, or, should one discover in such an examination that (as in, say the case of the food poisoning) there was no way to avoid the act that caused the remorse it should immediately occur to one who understood this distinction that there was a possibility that there was no guilty act involved -- that one was under some sort of dilusion.
What we need to keep in mind, thinking about kamma is that kamma did not result from morality, morality results from theories about kamma. Kamma is strictly a law of physics. Intentional action producing subjective experience. Where there is no intent there is no reaction to be subjectively experienced. Once kamma has been reformulated into morality, it assumes a power of it's own (bad ditthi, low view), and then acts involving wrong intent are possible (for example: assuming guilt for an act that does not warrant it).
H: So would I be correct in connecting the idea of Kamma with that of emptiness? -- You said that by placing guilt upon the self, one is causing suffering thus causing bad kamma. This suffering has its root, mula, in the connection of the event with the self, saying it was 'I' or 'me' who caused the bad thing to happen. Just as in the concept of emptiness where one views emotions that arise in the here and now objectively. In stead of connecting this emotion to the self or to another person one simply watches and views the emotion as it begins, remains, and ends. The Kamma produced by fealing guilt is a result of the connection of the result of the bad action with the self, saying 'I did it.' Instead, one should see the bad action and view it objectively and not involve oneself in its beginning, middle, or ending. Learning from that action and realizing the Kamma that was inherent in it, then adjusting the behavior accordingly to avoid such things from happening again.
In broad terms, kamma is what is obstructing emptiness, so yes.
Kamma is in it's essential nature a subjective thing, so it is correct to say that the root of Kamma is identification with kamma-producing action. (I am sure you realize that it is not just saying "I did it" that causes identification with an action.)
When you speak of watching as emotions arise, persist, and end, I believe you are drawing from the technique described in the Satipatthana, not the technique described in the Emptiness sutta. Not a bad thing to do, just a matter of technical detail; the "Emptiness" method is one of using concentration on ever more narrowly defined (or more refined) constructs to "empty" the mind of broader ones.
The kamma is not caused by the feeling of the guilt or remorse, it is caused by knowingly doing a wrong action. The remorse is the rebound. I drew a distinction between the kamma that caused remorse and the kamma that caused injury in order to show how it was possible to create false remorse based on incorrect understanding. Said another way: it is possible to cause remorse in one's self without having a good reason for the remorse; but it is not possible to cause intentional injury without causing one's self remorse. That said, your statement that this (experience) is a result of the connection of the result of the bad action with the self is correct, and the method you describe of objective evaluation is good technique.
Then I think we can go a little further with this: A person who intentionally committed an injurious act would be bringing remorse upon themselves. But what is often the case is that a person will add to that remorse unnecessarily, stimulating tears and lamentation and creating all kinds of ruckus. All of that is unnecessary editorializing on the fact and is a creation of false remorse on top of real remorse. The energy would have been much more productively devoted to this objective examining you suggest. Take your punishment like a man and learn from it...something like that.
H: I am a little fuzzy on the distinction you made about the emptiness sutta and the idea of viewing things objectively as they arise, remain, and conclude. You said: '"Emptiness" method is one of using concentration on ever more narrowly defined (or more refined) constructs to "empty" the mind of broader ones.'
And in his essay, Thanissaro Bhikkhu said:
"If, however, you can adopt the emptiness mode -- by not acting on or reacting to the anger, but simply watching it as a series of events, in and of themselves -- you can see that the anger is empty of anything worth identifying with or possessing . . . When you see this, you realize that labels of "I" and "mine" are inappropriate, unnecessary, and cause nothing but stress and pain. You can then drop them. When you drop them totally, you discover a mode of experience that lies deeper still, one that's totally free. . . . To master the emptiness mode of perception requires training in firm virtue, concentration, and discernment. Without this training, the mind tends to stay in the mode that keeps creating stories and world views."
It would seem that, just like the leg muscle attachment thing[3], that involvement in the concentration with, lets say, the noise of the city surrounding Migara's Mother's castle is infinitely more attached to the world than the concentration on only the castle itself. This new view is totally void of the perception of the noise that is coming from the city surrounding the castle. This process continues on up, continuing to narrow the scope of perception, and at a certain level one is perceiving only the manner in which things come into being, persist in existing, and then come to an end.
As I understand it, in the same way does the Kamma of a situation become evident when one limits his view to merely viewing the occurrence as it begins, persists, and then ends. This detachment is achieved by the following of the Aristocratic Multidimensional Way, freeing ones perception of the low views, low works, low talk, low . . . ya know. The Aristocratic Multidimensional Way is the emptying of ones life of superfluous behavior, thought, and speech that are downbound to the world of pain and suffering.
Bringing my point back to the topic above, I see the connecting of the self to such downbound feelings such as superfluous guilt as the broadening of ones perception of these things, the opposite of emptying it. This involvement, or indulging, in the suffering is the cause of the bad Kamma that arises from not behaving in accordance with the reality of the situation, in accordance with the Aristocratic Multidimensional Way.
What is your opinion on this connection?
Your understanding actually seems remarkably free of fuzz!
Your contrasting of the emptiness technique and the satipatthana technique is accurate I see nothing amiss in this method you are developing for your practice. This is exactly as it should be. You are taking a bit from here that works for you and a bit from there that works for you; and I believe that is how it should be done.

V: What if (hypothetically) one did not think (ie. it never occurred to them) that what they were doing was wrong? I'm thinking of my example of "pulling weeds" as killing living things. I would guess that most people don't give it a second thought. Would these people therefore, have caused no bad kamma for themselves, because of their ignorance? Is ignorance of harm equivalent to "no intent" to harm?
In the case of it not even occuring to one that one is doing harm, there is no kamma. This must be understood to be being said in the absolutest of hypothetical terms. I say that because what constitutes knowing and intent can be very subtle...to the point of near-unconsciousness. (One would need to be aware that one was "killing the weeds," for example; that is what one set out to do; and it is hard to pull weeds and not see some of the disruption one is causing such creatures as worms, etc.)
On the other hand we also have cases in the suttas where it is pointed out that merely by walking one is injuring countless living beings but that because there is no deliberate intent to injure there is no kamma involved. Here you have a case where there is knowledge and yet there is no kamma because there is no intent.
The murkey ground comes in in cases like building a fire. The Bhikkhus do not make fire except in extreme situations. This is because it is understood that fire kills countless living beings just by burning. So there is some gray area there between doing a necessary deed that injures living beings as being done without intent to harm and doing the same deed when it is unnecessary as implying intent to harm and therefore causing bad kamma.
While I am of the opinion that this kind of thinking, thinking in ethical terms, is a very high form of thinking for one in the world, we must remember that the objective here is the escape from all kamma. Consequently, the fine details of how kamma works should not be the highest priority on our list of things to be thought about. We need to understand the mechanism of action in terms of how it applies to rebirth: the intentional doing of a deed (any deed), grounded in desire, carries intent that implies identification with the deed and consequently downbinds the individual to the outcome of the deed in one form or another in the future. You can take it in the form of gross outcome spread out over long periods of time, or you can expend energy here and now in the effort to get beyond kammic outcomes. We do need to understand that it is intent that is the mechanism of action because without that factor being critical to the subjective experience of kamma, there could be no escape from kamma for individuals.
I think we need to remember the simile for the way we should think about food. On the one hand we should act with compassion and regard for all living creatures seen or unseen. On the other hand we need to accept the fact that simply by opting to live in the world we are bringing down harm on innumerable living beings and a whole heap of bad kamma on ourselves. We want to vigerously train ourselves to abstain from the gross deeds of killing large animals and humans, theft, and telling lies and we want to be stearing our lives towards that time when we give up the world in order to rid ourselves of the remaining bad deeds, but we should not be obsessing about the unavoidable.

V: This is an excerpt from "The Way to the End of Suffering" by Bhikkhu Bodhi regarding the definition of "taking of life" which he says only pertains to "sentient beings" thereby excluding plants.
Abstaining from the taking of life (panatipata veramani)
Herein someone avoids the taking of life and abstains from it. Without stick or sword, conscientious, full of sympathy, he is desirous of the welfare of all sentient beings.
"Abstaining from taking life" has a wider application than simply refraining from killing other human beings. The precept enjoins abstaining from killing any sentient being. A "sentient being" (pani, satta) is a living being endowed with mind or consciousness; for practical purposes, this means human beings, animals, and insects. Plants are not considered to be sentient beings; though they exhibit some degree of sensitivity, they lack full-fledged consciousness, the defining attribute of a sentient being.
First we must distinguish between "precept" and "kamma".
The Precepts are "Training Precepts". They do a "good enough" job to get you started, but they do not pretend to mirror kamma. For a mirror of kamma one needs to look to the Magga. (In this discussion Bhikkhu Bhodhi is not making the distinction between the two very clear.)
Even so, the Precept tells us:
"Train yourself to abstain from harm to living beings"
P¤¼¤tip¤ta: p¤¼a: breathing thing; atip¤ta: at tack, a pat (PED goes quickly from attack to murder; I am suggesting this goes to far too fast and includes every injurious act: i.e.: harm.) Plants breath.
The Magga makes the situation absolutely clear by the use of the word: avihi¸sa (a=no; vihi¸sa, do you hear the violinsa? absense of violence, harm, cruelty.)
Kamma has no period of training, for one. But I am not sure (actually I am completely without doubt) about the limited definition given to living beings mentioned by Bhikkhu Bodhi for the precepts. In quite a large number of places throughout the suttas you will find injury to plant and seed "life" coming under the scope of that harm to living beings which should be abstained from. (For just one such reference, check out the section on Mere Morality of the Brahmajala Sutta of the Digha Nikaya. -- The first sutta of the Long Discourses of the Buddha right up front after the introductory materials) In many places plants are referenced as "beings of one sense" (touch).
Secondly, I do not see in the concepts of "pani" or "satta" the idea of "sentience" as excluding plants. (I think satta may have a more exclusively animal implication); there is even less ground to exclude plants if we use the word sentient, a thing that senses. I have seen with my own eyes, a plant that "sensed" it was on it's side, using water pressure to attempt to right itself; I saw it attempt, I saw it get tired, and I saw it rest, and I saw it attempt again, over and over until it succeeded. Many peoples will tell you that plants speak to them. When this is said it uses the term "speech" incorrectly, but there is no easy way to explain what is happening: one is being "shown" pictures and connections to thoughts are being made.
PS: I also think Bhikkhu Bhodi has misunderstood the following:
He states: "Each principle embedded in the precepts, as we will see, actually has two aspects, both essential to the training as a whole. One is abstinence from the unwholesome, the other commitment to the wholesome; the former is called "avoidance" (varitta) and the latter "performance" (caritta)."
A careful examination of what is intended by the idea of cultivating the good will be found to be the development of states that are also characterized by abstinence, giving up, letting go, not doing: "without wanting, dislike, and blindness". Essentially the idea is spelled out in Samma Vayama:
Stop doing bad things you currently are doing
Refrain from starting up new bad things
Keep on with habits that you currently have that involve not doing bad
Develop habits that you currently do not have that involve not doing bad
I cannot stress enough that it is not possible to attain Nibbana where doing is required. The system absolutely depends on the fact that there is no bad kamma from any act of not doing. Similarly, there is no good kamma required: we are trying to get above, beyond kamma here; this is not done, in it's essence, by way of kamma . . . but . . . please understand, I fully agree with the idea that beginners should first set out to create a nice savings account of good kamma as a fall back position!.

[1]The Questions of King Milinda, while held to be orthodox Theravada texts, are not the word of the Buddha. For the most part Nagasana does not even claim that he is repeating the word of the Buddha. And that is a good thing, because he is often off the mark.
[2]Reference the similes of the salt in the barrel of water and the rich man and the poor man who both steal pigs. See: ThePaliLine - Giving.
[3]See: DhammaTalk: Sitting Practice: Leg Muscles and Attachment.