Karma, depending on how open you are to possibilities, and attuned to what really goes on in the world is either nonsense or fact. Karma is one of those life forces net everyone agrees may exist. karma is either real for you or it is not.
What is karma exactly is another question. Some who are familiar with the Christian bible relate karma to a biblical verse(es) about the sins of the father being visited on the sons down to the third generation. Other people think of karma as something that is paid back in your next life for things done or not done in this life. Some see karma as a type of immediate feedback machine. Others see karma as lifetimes of progression to an end state. Of course some see karma as an invention of the ignorant.
For myself and my world Karma is all those things and more. It seems obvious that because we are eternal beings as the bible and most major religions hold to be true, it certainly plausible that what I may do in this live could have consequences that follow me into future lives. Perhaps I am to do, or did something that makes a change to the world of the future. I will be born into a world where I live with the effects of the change I incurred in this lifetime.
Of course believing in reincarnation lends itself to thinking it is viable that what I do, or do not do in this life, is either rewarded or punished in a like fashion in a future incarnation. For example if I were to murder someone, and was found not guilty in a court of law, I am subject to the karmic effects of the murder I committed. On the other hand, if I were to live a saintly life, I will be rewarded in my next life for what I accomplished in this life.
Believing in karma as a function of reaching an end state of perfection brings a belief that I am mobile in each lifetime and either have climbed up or climbed down the karmic ladder. Living a good life in this lifetime moves me up a rung on the ladder when I live the next life. Doing poorly with this life, drops me one or more rungs on the karmic ladder.
Of those who believe karma does not exist except in peoples minds, it is hard to comprehend for those that have a belief system how karma does not play a part in ones ultimate fate. After all one is judged on ones actions and if that is not a function of karma with finality, I am at a loss to think of what may be a refection of karma. Calling a cat a dog does not change the name or nature of the animal.
For myself, I see all these beliefs or reflections of what karma is and how it functions very limiting. We like to categorize everything in our life, placing everything in it own little compartment. Most of the time how we categorize those things in our life makes little difference. With a belief system, or something as dynamic as karma, that is like classifying a brilliant diamond on one facet, ignoring or choosing to be ignorant to the idea that there is more than what we see or choose to see.
How about the possibility that karma is everything and more than I mentioned? What if karma is dynamic, far reaching across generations, and does move you and I up and down the karmic ladder of life, and also provides real time feedback on how we are managing our spiritual life? This more holistic approach is more rational than trying to place something like karma in a little box on the shelf.
Right now, if I am lonely, feeling lost, separated, or life just is not going where I want my life to go, it is immediate karmic feedback on how I am managing my life? Perhaps I am intentionally ignorant, or blissfully unaware that my actions at this moment, or this day, affect how the world interacts with me tomorrow, and how I interact with it? It is so much easier to find an external source for our problems, or life struggles than it is to take some introspective time and determine what we are doing or not doing to create the world we are living in at this moment. Why not take some time to ponder what you personally are doing to make your world a world you want to live in, instead of settling for a world you must endure?