Another presentation ... (this webpage has very good detailed
explanation on karma)
http://www.berzinarchives.com/web/en/archives/sutra/level2_lamrim/initial_scope/karma/brief_presentation_main_points_abou.html
The Four Factors Needed for Karmic Results To Be the Fullest
When we speak about a karmic action, four factors need to be
complete for the results to be the fullest. If any of these factors
is missing, the result will not be so strong. But that doesn’t mean
that there will be no results.
First of all is a basis. There needs to be a basis, a being or
an object at which the act is aimed. We thought that someone was in
the bathroom too long and we started yelling at them, but then it
turned out that there was nobody there. This is not as strong as if
there actually were someone there. There has to be someone who
hears our yelling, understands it, and believes that we mean it. If
the person is deaf or had the radio playing and couldn’t hear us,
it is not so strong.
The second factor that needs to be complete is the urge, meaning
the karma itself, and the other factors that accompany the urge. So
there needs to be a correct distinguishing of the object. For
example, I thought that was my umbrella that I took, but I was
mistaken and I took your umbrella by mistake. If we do this by
mistake, then it has a much weaker result than choosing the best
umbrella and taking it. But, even though we took it by mistake, it
is still a destructive action; it is just that it is not so strong
a destructive action. The second accompanying component is the
intention. If the intention is not there, it is like when we are
dancing with somebody and we didn’t intend to step on their foot,
but we did. That is much less heavy than if we did it
intentionally. Then the third component is that there needs to be a
disturbing emotion if we are talking about a destructive action. If
we kill a mosquito that is buzzing around our baby’s head and we do
it not because we hate the mosquito but we have love for our baby
and want to protect it; that is very different from killing the
mosquito because we hate it. All of that was the second factor, the
urge.
The third factor is the action. We have to actually do it. If I
was planning to yell at you, but then somebody came to the door or
the telephone rang and I didn’t actually do it, it is not as heavy
as actually doing it. If I just dreamt of killing you, I didn’t
actually do it in real life. Although that dream killing is a
destructive action and could be accompanied with a lot of anger and
so on and we could very intentionally kill the person in the dream,
it is not as heavy as killing the actual person because there is no
action involved.
Then the finale has to be there. This is the fourth factor. If
we shoot at someone intending to kill them and miss and just shoot
them in the arm, our action didn’t reach the intended conclusion,
so it is not as heavy. If we really wanted to hurt someone by what
we said and it didn’t hurt them at all, because they didn’t believe
us or whatever, it is not as heavy as if it actually had hurt the
person. The same if we lied and they didn’t believe us. We can see
that the results of our actions are really quite complex; there are
many different factors involved.