Nonpareil
The Terrible Trivium
We have to do stuff to create karma.
How does doing stuff create karma?
Is there any evidence for musical notes? Would they exist if there was no one to hear them?
Are you asking if the air would still vibrate at certain frequencies if there was no one around? If so, the answer is yes. If you are asking if the human system for classifying musical notes would exist if there were no humans, the answer is no.
Imaginary concepts like "justice" and "mercy" are also dependent on our minds interpreting situations.
Yes.
Yes, it's all internal. We're talking philosophy and art here, not empirical science. The only "evidence" is our subjectivity and our conscience.
So, in short, it's magical thinking bolstered by confirmation bias. It doesn't actually mean anything.
They have been just notions or concepts up until recently, but in the legal system for example, DNA evidence is now making justice more of an objective reality.
No. It's making the solution to the crimes an objective reality. But knowing who did it does not mean that justice is served. You said it yourself. Justice is subjective.
The reason I bought up evolution at all, is because the whole process is surely a form of natural justice.
No, it isn't.
EDIT: Oh, and have we found out what it is that astrology does yet?