Modern ideas of justice are based on the essentially religious notion of obedience: abide by these rules or go to hell.
So punishment exists to keep people in line - to make them obedient.
The idea there, presumably, is that most humans are irresponsible halfwits who would go around misbehaving if there was no threat of being punished for their transgressions. I know I'd certainly be murdering and robbing willy-nilly if it wasn't for the threat of legal action.
The other great guardian of behaviour is karma. Based on a traditional Indian notion of eternal payback in the form of reincarnation, it suggests that we will all get our comeuppance.
The idea of paying for sins committed in this life by being reborn as a snake or an earwig is certainly gentler than an eternity of hellfire, or the electric chair, because at least the karma/reincarnation option offers the possibility of redemption. But it is still essentially crime and punishment - obey or else. And it undermines the notion of free will.
Clearly society can only really work if we all agree to abide by a certain set of rules. Anarchy is neither workable nor appealing.
However, there is a huge difference between obedience out of fear and agreeing to abide because we're grown up and reasonable and essentially not that bad in the first place.
Given free will to choose, most of us will choose (the greater) good without threat of retribution.
There are all kinds of details and differences in the various beliefs around karma. In its original, religious form, it is intrinsic to the notion of reincarnation. But the generalised Western sense of karma that we have chosen to adopt and adapt is based on a balance sheet of right and wrong.
It's really just the name 'karma' we have adopted to cover a system we have long had faith in, a system where "what goes around comes around" and "good things happen to good people".
This version of karma is comforting and anything that offers comfort and consolation is not to be sneered at. If it happens to be a toasted banana and Nutella sandwich or a favourite blanket or a faith in karmic justice, comfort and consolation are always good.
Karma helps us accept the bad things that happen because essentially it offers the prospect of revenge.
We've been brought up to believe that revenge, although appealing, is somehow wrong so we delegate that responsibility to karma. And if it allows us to let go of festering bad feelings then "go karma".
It might also help us release feelings of injustice or resentment - if someone treats us badly it can be nice to know that they're going to get theirs thanks to the big K.
But karma has a flipside for people who suffer too. I was amazed some years ago by a conversation with a woman whose perfect, healthy 19-year-old son was paralysed from the neck down in a Sunday morning rugby game.
She said more than one person had asked her, in the face of tragedy, what she thought she had done to deserve it.
To me it was profoundly shocking that anyone would believe something so awful could ever be deserved, or that any kind of higher power would not only permit, but dish out, that kind of suffering.
So many people are affected by accidents like that - did they all deserve it? Will they all get some kind of payback? And what kind of payback would it be worth?
I was always told that good things happen to good people. I really like the idea but I've spent the guts of half a century lurking on this planet and good things happening to good people is simply not the truth that I see.
I don't know if I believe in reincarnation. Possibly not. Otherwise how would the world's population be exploding so much?
But I certainly don't believe in karma. Very simply, I know too many good people who have had rubbish things happen to them and too many rubbish people who get away with it.
There is no question that there are lots of incidences where people do get comeuppance, although I'd dispute some of the examples people give.
Like the anti-Semitic Hungarian politician who later discovered his grandparents had been killed in Auschwitz.
Apart from the fact that this is irony, not karma, even if it was cosmic payback - who got paid back?
Or last year's story of Billy Ray Harris, the homeless man who returned an engagement ring that had been accidentally dropped in his hat. Within a week he had been given a home and lots of money. That's not karma either.
There was no mysterious force bar the internet. He did a good thing, people liked it and rewarded him - not karma, just nice.
The concept of karma could be said to apply in the story of Henry Ziegland who, in 1883, broke up with his girlfriend who subsequently killed herself.
The woman's brother shot Ziegland and then himself, but Ziegland did not die. The bullet intended for him grazed his head and lodged in a tree behind him. Many years later Ziegland decided to use dynamite to get rid of the tree. The explosion caused the bullet originally intended for him to blast out at force and kill him.
Although the concept of karma could be said to apply there, I don't think it does because, despite wanting to believe in some kind of cosmic justice system, I can't.
I'd call Ziegland and his bullety tree a coincidence - a wild one, but aren't they all really? The reason I don't believe is that karma implies fairness and justice on some great level, but I don't see it. A lot of good people go through things that are simply not fair.
I don't believe in fate or destiny either, just in luck. Where, when and how you are born comes down to luck. What colour eyes and what arrangement of parts you have is also down to luck. Sure there are genetics involved but the precise arrangement of those genes is down to chance.
A lot of health - the greatest wealth - is down to luck. The chances we get, or don't get, the people we meet, the accidents we have, or don't have - all luck.
Luck covers all kinds of things and there is no 'deserving' to it. No-one deserves tragedy and no-one deserves to win the lottery, it is chance, pure and simple.
The area we do have control over is energy. We all have energy, it's the conundrum that baffles scientists about death as energy cannot die.
There are individuals and places that are referred to as having good or bad karma and that makes sense in an energy kind of way.
Some people are nice but they creep you out or tire you out or depress you. Other people make you feel good, energised, positive.
It takes work but we each have quite a bit of control over the energy we give off and that has an effect on the way life pans out.
Negative energy is toxic to ourselves and all around us. If luck is the force majeure that we cannot control, energy is the force that we can control and that defines how well we live with the hand we are dealt. Energy is what decides if we are happy or not and that in turn influences lots of things that could, perhaps, be construed as karma.
We have all been treated badly on occasion, the same as we have all behaved badly on occasion, but for most of us there are instances that particularly rankle, people whose behaviour towards us seemed especially unkind and unwarranted. I like the idea that people who have treated me badly will get a nice fat payback one day. Indeed some of them have had things happen that could be construed as a kind of karmic resolution.
But chances are that anyone who has treated me badly has treated lots of people badly because they just aren't that nice.
Often people behave poorly because they are unhappy or damaged; the revenge is simply that you get to walk away while they are stuck with themselves.
And more often than not the putrefaction that lives within them turns against them. In my mind that's not karma, but simple cause and effect.