A few hundred years ago, many people grew their own food, made their own clothes, and built their own homes. And when they saved, they really were stocking up actual stuff that they would consume at a later date. Markets and currencies existed, as did collective schemes to stockpile goods for hard times, but the degree to which people relied on them to provide the day-to-day needs of life was relatively limited.

Today, our reliance on markets and currencies is all-encompassing. Almost no one grows their own food or makes their own clothes. Instead, we all do one particular thing — we have a job — and that gives us money to buy all those other things. So we don’t “save” actual material goods. We save money.

And this is where things get weird. Because you can’t eat money or wear it or shelter yourself with it. You can only spend it. Money is the legal ability to consume stuff that other people have produced. Saving money is just stocking up on the chance to take advantage of that legal ability at a later date. Similarly, your retirement savings allows you to legally live off what other people produce at whatever point in time you’re retired.

But the money you “save” doesn’t just sit there like wheat would.