We must not misunderstand that karma is fatalistic or
deterministic.
and I think this is v important to consider:
"Listen, Sivaka. Some kinds of feeling arise with bile as
condition ... with changes in the weather as condition ... with
inconstant behavior as condition ... with danger from an external
source as condition ... with kamma-results as condition. Any
ascetic or Brahmin who is of the view that, 'All feeling is
entirely caused by previous kamma,' I say is
mistaken."[44]
(also note that there are five kinds of conditionings, see http://www.geocities.com/Athens/Academy/9280/kamma1.htm)
And yes our thoughts and behavior are not predetermined. They are
arising conditions, but they are not 'predetermined' by anything,
because if it were, then as the Buddha said (Misunderstandings of the Law of Karma):
"Bhikkhus, of those three groups
of ascetics and Brahmins, I approach the first group and ask, 'I
hear that you uphold this teaching and view ... Is that so?' If
those ascetics and Brahmins, on being thus questioned by me, answer
that it is so, then I say to them, 'If that is so, then you have
killed living beings as a result of kamma committed in a previous
time, have stolen as a result of kamma done at a previous time,
have engaged in sexual misconduct ... have uttered false speech ...
have held wrong view as a result of kamma done in a previous
time.'
(cont.)...These words discourage us from going too far with kamma
by considering it as entirely a thing of the past. Such a view
encourages inactivity; passively waiting for the results of old
kamma to ripen and taking things as they come without thinking to
correct or improve them. This is a harmful form of wrong view, as
can be seen from the Buddha's words above.
Significantly, in the above passage, the Buddha asserts effort and
motivation as the crucial factors in deciding the ethical value of
these various teachings on kamma.
The Buddha did not dismiss the importance of previous kamma,
because it does play a part in the cause and effect process, and
thus has an effect on the present in its capacity as one of the
conditioning factors. But it is simply one of those conditions, it
is not a supernatural force to be clung to or submitted to
passively. An understanding of the Principle of Dependent
Origination and the cause and effect process will clarify
this.
For example, if a man climbs to the third floor of a building, it
is undeniably true that his arriving is a result of past action --
namely, walking up the stairs. And having arrived there, it is
impossible for him to reach out and touch the ground with his hand,
or to drive a car around. Obviously, this is because he has gone up
to the third floor. Or, having arrived at the third floor, whether
he is too exhausted to continue is also related to having walked up
the stairs. His arrival there, the things he is able to do there
and the situations he is likely to encounter, are all certainly
related to the "old kamma" of having walked up the stairs. But
exactly which actions he will perform, his reactions to the
situations which he meets there, whether he will take a rest, walk
on, or walk back down the stairs and out of that building, are all
matters which he can decide for himself in that present moment, for
which he will also reap the results. Even though the action of
walking up the stairs may still be influencing him (for example,
with his strength sapped he may be unable to function efficiently
in any given situation), whether he decides to give in to that
tiredness or try to overcome it are all matters which he can decide
for himself in the present moment.
Therefore, old kamma should be understood in its relation to the
whole cause and effect process. In terms of ethical practice, to
understand the cause and effect process is to be able to learn from
old kamma, understanding the situation at hand, and to skillfully
make a plan of action for improving on and preparing for the
future...