The law of karma obeys our notion of natural justice - rewards for good behavior and punishment for bad behavior.
When this does not happen in life we project it into future lives giving rise to the idea of reincarnation.
The principle of natural justice does not seem to apply in life.
Job says,""Why do the wicked live on.....and no rod of God is against them.'" Job 21:7a,9b (NRSV)
Perhaps these ideas are not universal laws at all.
Paul says to waive judgment according to understanding.
But life is not chaos.
There are constancies - day and night, summer and winter, light and dark etc..
Newton's laws apply.
But even Newton's laws break down with the very small (atoms) and the very large (galaxies).
So where does that leave us?
We have free will to make choices.
But even our free will is conditioned by our experience.
We make mistakes.
In human experience the chances are that if we treat people badly they will treat us badly in return.
But this is not a law.
People may choose to return good for our bad behavior.
So laws and rules are not what govern our lives, they are merely guidelines for our well-being.
The cause and the purpose of life is love.
[Scripture quotations (marked NRSV) are taken from the New Revised Standard Version Bible, copyright 1989 by the Division of Christian Education of the National Council of the Churches of Christ in the U.S.A., and are used by permission. All rights reserved.]