Karma exists not as a physical reality, but as a psycho-spiritual reality for all self-aware beings.

I will be using the same argument as I did the last time I initiated this debate: In the Buddhist tradition, Karma is a different concept than what we believe it to be in the West, and I'm trying to explain that. Karma is Sanskrit for Action, so when a Buddhist tells you that your situation is your own Karma, he means that it is your own action. We create our situations in our minds: objectively, there is only BEING independent of any situation. Like a cached web page, most of the information about our situations is not based off of raw sense data, but what we are used to interpreting our situations as being. For example, every time you enter a hotel room, are you quickly accustomed to it, or do you go around examining and toying with everything to get to know the new room? Most adults tend towards the former. This is because we already have the concept of "hotel room" in our minds, so the brain doesn't need to integrate nearly as much information about where we are in order to realize that it is a hotel room. Our concepts, including our self-concepts and our worldviews, are all inductively derived. Since you cannot become aware of the true nature or "essence" of a phenomenon through induction, all of our "knowledge" is conventional and relative rather than objective and absolute. All situations, including those in which we are excited or angry, content or frustrated, fulfilled or anguished, are created by the mind. If we cultivate attachment and hatred, we are more statistically likely to be in a distressed state. If we cultivate self-efficacy and a positive and compassionate attitude towards life and everyone else in it, we are statistically more likely to be in a state of fulfillment. I will demonstrate these individually. Addiction is a great example of attachment cultivated in the past causing suffering in the future. Say that I do heroin. The more heroin I do, the more accustomed I become to the high state, and the less accustomed I become to sobriety. The more accustomed I am to being high, the more I crave it. In my endeavor to notice my high, I progressively do more and more heroin, and the more and more alien sobriety becomes to me. When I have come down all the way, it's like I've had my warm, cozy blanket torn off me and I've been thrown out in the cold. I'm now in a situation where I will have to face suffering no matter what because of my past actions: but the more I delay the suffering of withdrawal by continuing heroin, the deeper I entrench myself into it. Say you take the attitude that everyone else is bad. You are more likely to treat them badly, so they are more likely to take the attitude that you are bad and treat you badly, so you are more likely to continue believing that they are bad and so you continue to treat them badly. You have started with a seed of distaste for others and sewn it in your actions towards them. They helped to nourish it: together, you grew a hatred plant. Let's review. The more regularly you consciously desire something and fulfill that desire, that desire will remain, but the fulfillment will not. Also, your attitude towards others is likely to affect their attitudes towards you. If you go into life attempting to contribute something new to the world and to connect with others, your fulfillment will be based on the value of the principles that you stand for and the value of the connections you have made with others. If you stick to your principles, you will be self determined. If you approach others compassionately, you will gain from their happiness and you will be motivated by their suffering. All this leads to a deeper feeling of connection between the individual and the world in which he exists. The individual will feel like a real thing within the world, something inseparable from existence that is dependent on what is and one of the determinants of what will be. This, I define as self-actualization. It's opposite, isolation, is experienced by refusing to empathize and connect with others and by not standing for any principle, and will ultimately result in meaninglessness and a deep sense of unsatisfactoriness. Bonus for revic: Though your ex has no guilt for having cheated on you, she has "built karma" in this psycho-spiritual sense. In cheating on you, she gave into a desire for sex and paid the price by severing the relationship with you. Now, you might say "she didn't even care about me in the first place." In response, I say that the karma goes deeper still. I predict, based on her actions, that she will have to grow in order to be fulfilled in a relationship: I predict a lot of heartache in her future relationships, because I have assessed her character. Someone who cheats on a significant other does not understand the importance of US in a relationship. Your ex is a selfish individual who fails to communicate her feelings to her significant other (i.e. she cheated on you instead of breaking up with you), is unable to commit to "being a couple" and will be unable to have a fulfilled relationship because she is not focused enough on "us" to build a good relationship. No good comes out of being selfish in love. That is the karma: Hopefully you will understand this, and be able to exact the ultimate revenge on her by building a selfless, loving relationship, which she will never be able to do without changing herself on a fundamental level.