There are approximately three ways how your thinking affects your experience:
- Your thoughts can drive actions that directly influence the world around you, which in turn results in different sensory data that you experience.
- Your thoughts can drive your attention, which in turn drives what sensory data you get. Confirmation bias strongly at play here – if you think the world is bad, you’re more likely to notice evidence confirming it, and vice versa.
- Your thoughts influence what future thoughts you’ll have.
Mainstream interpretation of karma is via 1) – If you do bad stuff, the world will eventually push back. My take is that this may often be the case, but it’s more of a social dynamics than a physical law that the world operates on. In my opinion, karma is partly 2) and mostly 3).
Explanation of 3): Bad thought processes lead to more bad thought processes over time. What is a bad thought process? It’s a thought that you know (on some level) is against the wellbeing of a future you and/or other sentient beings.
Let’s say you are in a situation with options A and B, where you know B gives you a short term gain, but long term it turns into a loss. You are 50:50, hesitate for a while, but then end up taking B.
But thinking is adaptive. Next time you’ll be in a similar situation, it won’t be 50:50 anymore. You’ll be more likely to take B, especially if you already got the short-term gain, but not yet the longterm loss.
There is the positive reinforcement, but that comes also from just making the decision – there’s another form of confirmation bias: You are more likely to notice evidence that your decision was good, unless you actively do the opposite. Or, you simply learn that you can get away with it.
This will have a subtle influence on your future thinking, as it generalizes to the whole class of decisions. You are simply one step closer to the dark side. Over time, this accumulates and starts to have noticeable negative impact on both how you perceive the world and how your thinking and actions affect the world. This includes not just thoughts/decisions that directly influence the external world. It’s also all the subtle conscious and subconscious thoughts, like jealousy, greed, wishful thinking, dishonesty, …
Or to put it differently:
Let’s say a way of being exists where you are closely in touch with reality, which allows you to operate effectively in the world, you can experience the whole spectrum of human emotions, yet you choose not to experience suffering. Let’s say this is the desired way of being. I argue that for whatever way of being, doing mental moves such as jealousy, greed, wishful thinking, dishonesty, but also all the subtle decisions to take short term gain instead of long term one, moves you further away from the desired way of being. Whatever mental moves you’ve done that didn’t move you closer to the desired way of being will eventually have to be undone / redone in a better way. This is how I understand karma, and the accumulation of bad karma.