"My, how you've grown!"

We've all been there. Some of us longer ago than others.

You're visiting, or being visited by, an older relative, and you're standing there thinking that you'd far rather be playing football or climbing trees, and they utter those awful words "My, how you've grown!". Now how on earth are you supposed to answer a greeting like that? You could try the logical approach ("Yes it's because I eat lots of spaghetti, and it's long and thin..."), the contrary riposte ("No I haven't"), or the sociable rejoinder ("Yes, so have you"). You could even branch out into surrealism ("No, I'm standing on your head"). Growing just happens: it's not even interesting. Saying "My, you're breathing!" would sound no less daft to a ten-year-old. Although it might arouse the suspicions of his parents.

We grow, then we grow up. The English language has this amazingly economical way of saying not only that we have finished doing something, but also that we have exhausted all further possibilities of doing it. We eat, and when there's no more we've eaten up. When the stuff is all used, and there's no more to be had, it's used up. The only other language Lunchista knows of which shares this turn of phrase is Chinese: the little suffix "Le" at the end of a sentence tells us that whatever is going on in that sentence has now been completed. Sometimes "Le" also implies that whatever has been done, has been done to the point of perfection. So, we grow, and provided we stay healthy and have enough of the right type of food (spaghetti or otherwise), we reach the best of all possible heights and then we stop. We are then grown-up.

We are lucky that this is all done automatically. What would we do if it took some effort, or some choice, to switch "growing" off? Ten-year-olds grow at the rate of about 5 cm a year: imagine the chaos if that carried on throughout life. A typical retiree, at about 4 metres tall, would be nearly as high as a house.

Most people, given the choice, would like to be "slightly taller than average". So in the end, a choice about whether to stop growing or not would result in maximum possible growth: very few people want to be shorter than average.

Does the phrase "maximum possible growth" sound familiar? Isn't it what most governments, given the choice, would like their country's economies (their GDP) to do? But in a mature economy like ours, where everybody could easily have enough of all they need if the distribution were ever so slightly tweaked, do we really need more "growth"? How about two things to ponder over lunch:

First, think of all the goods and services we use: there's a physical limit to how much of all of them we can cram into our lives. We can only eat so much food, inhabit and fully appreciate so big a house, drive so many miles, take up so many sports, drink so much beer and read so many books: after that the enjoyment palls or we simply run out of time, health or natural resources.

Second, pick any easily-measureable number that represents quality of life: life expectancy, infant survival, people's perceived happiness, you name it, and plot it against income: all this can be done as a lunchtime's entertainment using Gapminder, who already have all the numbers. Of course you get a rising curve on your plot: it is better not to be poor. But, at a level of income just shy of the UK average, the curve flattens out. The very rich do not live any longer, or feel any happier, than the average Brit. We should delight in that curve. It tells us that the present halt in economic growth need not prevent us from having a good quality of life. It also tells us that economic growth is best left to the people in countries who really need it.

There's only one problem. Every time any money is created, so is a corresponding amount of debt. This debt incurrs interest. So unless we are all producing goods faster than this debt grows, there will always be more debt than the total wherewithal available to pay it off. Someone, somewhere, will always go bust. It could be you.

It is not a pleasant thought: we either put up with an economy that grows, providing us all with more of anything than we can ever sanely use, or put up with one that doesn't, launching us all into a game of musical chairs (or Russian Roulette, depending on your frame of mind) with the bailiffs.

So until we change the way that money is created, the economy can never be allowed to be grown-up.