Time is the simplest thing
Physics learned long ago that nothing happens in an instant. Einstein gave the universe a fourth dimension, and nobody in that field has managed without it since. The three spatial dimensions tell us what it is, the fourth dimension tells us when it I there.
Economics could use the same lesson. Too much economic writing treats a transaction as a single frozen moment, a flash of exchange with nothing before it and nothing after. Real economic life is not like that. It stretches and it waits. It pays for waiting, and it grows because of waiting.
Take interest first, because interest is the clearest evidence that time has a price. Interest is not what a lender extracts because they hold the whip hand. It is what a borrower pays because now is worth more than later. Give someone £100 today and you hand them certainty, choice, and the pleasure of the present moment.
Promise them £100 in a year and you hand them a hope. Interest is the gap between the two, priced by the market rather than by decree. Children famously demonstrated the same principle with marshmallows. Offer a child one marshmallow now or two in fifteen minutes, and you have built a miniature economy with a single, brutal choice, consume or wait. The children who wait are not smarter about marshmallows. They have simply grasped, at four years old, what half of economic commentary manages to miss at forty, that reward compounds when you defer it.
Savers do the same thing with money. Investors do the same thing with capital. An economy does the same thing with its entire stock of resources, choosing, collectively and imperfectly, how much to eat now and how much to plant for later.
And planting is the whole story of growth. Spending does not grow an economy. It moves money from one pocket to another, and the wheel turns with nothing new appearing. Growth needs seed corn kept back, not seed corn eaten. It needs machines built, skills learned instead of leisure taken, and research funded instead of profits distributed.
That is investment, and investment only makes sense if you accept that the future is real and worth sacrificing for. A society that spends everything it earns, the instant it earns it, stays exactly where it started. A society that saves and invests, even modestly, ends up with factories, railways, and research it did not have before, and those things go on paying dividends long after the sacrifice that built them is forgotten.
This is where a great deal of economic thinking goes astray. Saving gets treated as a kind of leak, a demand deficiency waiting to be topped up by borrowing or spending. That view captures a short-run worry and misses a long-run truth. The interesting question was never how fast saved money gets spent again. It is what that saving builds.
A pound saved and invested in a factory does something a pound spent on a meal never can: it keeps producing value long after the original pound has gone. Consumption satisfies today. Investment builds tomorrow's capacity to satisfy more, for longer, for more people.
A field of wheat is months of patience turned into food. A power station is years of patience turned into electricity for decades. Every stage of production sits at some distance from the final act of consumption, and the whole structure of an economy's capital is really a map of how far into the future its productive effort reaches.
Cheapen the price of patience artificially, force interest rates below what real saving would justify, and you tempt businesses to stretch that structure further than genuine sacrifice can support. The boom that follows is real enough while it lasts. The bust is the bill arriving for patience that was borrowed rather than earned.
None of this needed Einstein, and none of it needed advanced theory either. Farmers have always known not to eat the seed corn. Apprentices have always accepted low pay now for a skill that pays for decades. Entrepreneurs who reinvest outgrow rivals who cash out. Ordinary life is soaked in the logic of time, sacrifice, and delayed reward. It is only economics, oddly, that needs to be reminded of it.
Put time back where it belongs, as a genuine dimension of economic life rather than an afterthought, and the picture sharpens. Interest is not a technicality. It is the price tag on patience. Investment is not spending's poor relation. It is the only economic act that borrows from the future and repays with growth. Any country that wants to be richer in twenty years has to be willing to be a little leaner today. There is no way around that arithmetic, whatever the politicians promise, and anyone offering you a shortcut is only offering you the first marshmallow.
Madsen Pirie