Nothing for Nothing
My favorite analogy of this is a game of pool. You start with a nicely orderly set up, the balls racked in a neat triangle at one end and a pool player and cue ball at the other. Hit the cue ball, the rack is "broken", with balls scattering apparently randomly over the table. When a person chooses to hit the cue ball, that's karma. The action of the pool balls is vipaka.
Humans, with their innate need to make patterns, can see things in those arrangements of the balls -- three red balls together make a triangle, say -- and of course some of those relationships are used by a good pool player to predict parts of what will happen and plan their shots, but the arrangements of the balls at any one time is essentially meaningless, a transient happenstance. On the other hand, if you run that video in reverse, you can see how each ball's position at any time is in fact a consequence of some action in the past.
Buddhism sees the universe and everything in it as a configuration of the cosmic pool table, one that happens through cause and effect back through time. Some of those configurations have an apparent meaning -- we give them names and we look at them as "things".
My cat Ali'i is asleep under the desk, waiting for me to go to bed. I can look down through the glass and see him, and he certainly looks like something that has an independent existence, volition, a personality (wow, does he!) but if I think back over the ten or so years I've had him, he's eaten a helluva lot of cat food, and excreted it, he's shed hair and coughed up hairballs and accepted delicious cat treats diffidently but enthusiastically. He's very different from the kitten I brought home ten years ago, and he probably doesn't even share many atoms with that kitten now. And, he will go on exchanging atoms, and someday will die, like my Radar did in March, and those atoms will be scattered back to the universe where they will becomes part of something else forever and ever amen.
If we could watch the whole universe, all at once, we could see everything in the universe doing the same thing -- arranging and re-arranging, making stars and galaxies and unmaking them, forming planets and then planets dissolving as their star changes. But none of those things has any independent existence: no matter what, we could follow every atom back through history from wherever they happen to be now.
What's more, if we look more and more closely at those temporary arrangements, we can see they are made up of smaller temporary arrangements: cat, to tissues, to cells, to molecules, to atoms, to protons and neutrons, to quarks, and if we really looked, at the tiniest scale for the shortest time, we would see quanta appearing, existing, and disappearing, apparently out of nowhere.