Karma is simply a law of causation; actions lead to states. if you do things, stuff happens. Some philosophers don’t believe in causation (we can’ throw rocks through windows and the windows shatter, but we don’t have a direct experience of the causation between rocks flying and windows shattering, we only associate the two together) so the law of Karma ain’t absolute. But, if I throw a rock through a window, I can say, with 99% accuracy that the window will probably shatter although I have no direct experience of causation. I merely associate the two events together because they’ve happened together before.

Anyway, if you do stuff, things happen. That’s it. Swing your hand at a glass of water and watch it shatter to prove the law of karma to yourself.

Karma, when it comes to MORAL causation, says that if you do good things then good stuff sorta ripples outwards. The idea is that if you help a dude then that dude will be a bit happier. That’s all that means. Some may go on to say that that dude will be a bit happier AND he might go on to help others too. Or he’ll see value in helping or being helped and he’ll tell good stories about generosity. But, like I said, we have no direct experience of causation, so ALL we can say about moral causation is that if you do good stuff then someone, somewhere is PROBABLY going to benefit and feel good about it. Even that can’t be said with absolute certainty.

With the qualification that you like society and that you like people and that you think people ought to be good, YOU ought to be good to them (even if they are terrible to you) because then the world will be a SLIGHTLY better place. That’s why you’d want to help others, even if others despise you. Because it makes the world a better place and most humans want the world to be a better place. If you don’t want it to be a better place, then go ahead, be a dick to everyone who’s mean to you and make the earth a slightly crappier place to live. Do I believe in karma? Maybe not absolutely, but I’m pretty sure my actions lead to consequences and I’d rather those consequences be for the benefit of the planet.