If you were born in ancient Rome, you could expect to live 21 years on average. If you made it to your 5th birthday, you could expect to live 42 years on average. How is this possible? Surely, you are 5 years closer to your 21st birthday and therefore should only have another 16 years to live on average? Your five years of ageing have actually increased your life expectancy, and you’re now further away from death than you were at the instant you were born. It’s almost as if we’re ageing in reverse.
Life expectancy increased because – by reaching the grand old age of 5 – we escaped many of the ailments that cause premature death. For humans, there is a limit to increasing life expectancy: ultimately, we are perishable, and we can only cheat death for so long. But ideas are non-perishable; so are books, and so is knowledge: if they’re good enough, they can persist in perpetuity.
Non-perishable items such as ideas, books, and knowledge follow a different rule: their life expectancy depends on how long they’ve already been around. If a book has been in print for 50 years, it will still be in print in another 50 years, on average. Crucially, if it reaches its 60th year in print, we can expect it to be in print for another 60 years. Knowledge truly does age in reverse.
This concept is known as the Lindy Effect, described by the legendary Benoit Mandelbrot in his book The Fractal Geometry of Nature. It can help us develop the canon: inevitably, in a time-constrained environment we must make decisions about what to put in and what to leave out. So how do we choose what to teach? We use the Lindy Effect.
The ideas and knowledge that have been taught for the longest are likely to remain important for at least as long as they’ve been around. Shakespeare’s works have been studied and enjoyed for 400 years, and will continue to be for at least another 400; Newton’s laws have been known and taught for 350 years, and will continue to be for at least the next 350 years.
Progressives often argue that much of the knowledge taught in schools is antiquated and that the knowledge and skills we are teaching ill-prepares our pupils for the 21st century. What they don’t understand is that old knowledge will be even more important and relevant in the future because of the very fact that it is old: it is knowledge that has stood the test of time and been found to be relevant and useful generation after generation.
We like to think that the new will supersede the old, but it’s an illusion: the failure rate of the new is much greater than the failure rate of the old. Things that are prone to ageing are already dying or dead. As Olivia Dyer of Michaela School mentioned on Saturday: nothing ages as fast as the cutting edge.
Using the Lindy Effect to help us teach.
The utility of the Lindy Effect doesn’t stop there. It can also guide us in how to teach. For thousands of years, teachers have been standing in front of classes and talking to pupils with the aid of something to write with: chalk and talk. The job of a teacher is very simply to explain and to guide; to coach and to mentor. What the Lindy Effect tells us is that this will continue to be the way we teach for another few thousand years.
iPads and tablets may indeed revolutionise education and fundamentally change the way we educate pupils. But given they’ve only existed for 10 years, we can’t even be sure that they’ll survive the next decade, never mind the next century; in complex systems, time is the ultimate arbiter of what works and what doesn’t.
Jobs of the future
Have most of the jobs of the future really not been invented? More or Less debunked this recently, but even if it were true we can use the Lindy Effect to realise that many jobs that exist today will still exist for the duration of our pupils’ lives: accountants, lawyers, doctors, scientists, engineers, architects, bankers, computer programmers to name just a few. These jobs aren’t going away, and they’re going to make up a sizeable proportion of the jobs available to our pupils.
Not only that, but the jobs that don’t exist yet are precisely the ones that are unlikely to last very long when they do come around: we couldn’t predict in 1992 that mini-disc salesperson would be a job, but knowing the Lindy effect, we shouldn’t have been too surprised when Sony announced that the last minidisc players were sold in March 2013.
With teaching and knowledge, we should respect the knowledge, the books, and the techniques that have survived the longest: they’re old for a reason.