There was a massive fuss last week about the UK Greens’ plan to restrict the term of copyright to 14 years, whilst also replacing the current benefits system with a guaranteed basic income that would prevent people with other things to do being forced into paid employment .
Suddenly, left-leaning writers who generally claim to believe in fairer distribution of wealth and in individual sacrifice for the greater good found those principles, um, somewhat tested .
There’s a really basic economic point underlying copyright and patent law, which non-economists often miss: the marginal cost of distributing existing works is zero and the marginal benefit is greater than zero.
It’s absolutely clear that restricting the distribution of ideas and their expression (and copyright is literally that: it grants a state monopoly to an individual or company on the expression of a particular idea) makes society worse off, once that idea has been expressed.
To use an example: the cost to society of you reading the Harry Potter series is zero. The benefit to you of reading the Harry Potter series is greater than zero, so the optimal solution for the world is for you to read the Harry Potter series for no cost. If the price is greater than zero, that means that there are some people who would benefit from reading the Harry Potter series and who are not doing so, even though it would cost society nothing to give them it for free.
This is true for all pieces of media, all computer programs, and all drug and machinery patents that exist. Provided that they exist now, society would be better off if the state monopolies that have been granted for these works were immediately abolished.
Of course, “provided that they exist now” is the rub here.
The justification for the introduction of copyright and patent law was that it is in the common good to accept this monopoly intervention, even though it overrides actual property rights (you are banned from assembling a selection of actual items that you own into a particular shape), in order to incentivise people to come up with new ideas.
This is clearly true for a certain period – with no copyright monopoly at all, there’d be no Hollywood or computer games industry, and fewer books . But, like all government interventions to create private monopolies, it should be carefully regulated to ensure it continues to act in the public interest.
It is utterly ridiculous to claim that maintaining this monopoly for 70 years after the creator’s death is required to incentivise anyone.
My intuition, which could be wrong, is that the UK Greens plan for 14 years after publication  isn’t far from the right number.
If a book or film or record hasn’t sold any copies after 14 years, it’s not impossible that you’ll end up being the next Moby Dick  or the next Plan Nine From Outer Space, but it’s distinctly unlikely. More research into the sales profile over time after publication of different types of media would be handy here, but I would be surprised if it isn’t, on average, an exponential decay curve.
Even for 14-year-old bestsellers with significant annual sales in absolute terms, these will usually be a small fraction of the total sales generated near release .
The answer may well be different for different types of media – and there’s precedent for this, given that the innovation shown by drug developers and industrial designers already gains them a far shorter monopoly period than media producers are granted.
But whatever the exact number is, it’s an empirical question that we should be asking, and it’s a hell of a lot shorter than it is now. Even at its absolute worst, the UK Greens proposal shifts the window of discussion in the right direction.
 Or would have done, had they understood the fact that copyright is a state-granted monopoly that makes society worse off.
 Academic books don’t make any money in their own right, and nor does literary fiction, so the biggest loss to readers from total copyright abolition would be the disappearance of middlebrow bestsellers.
 The definition of ‘publication’ is another point here: if copyright were restricted to a very short term, we’d need a mechanism to ensure that sending a copy to an agent or A&R scout didn’t set the publication timer going, or new artists spending 10 years shopping a book around agents would be unfairly disadvantaged.
 And ideally still alive at the time to enjoy it, unlike poor dead Herman Melville.
 Yes yes, Game of Thrones, I know.