You're confusing use-value (the intrinsic value of something) with exchange-value (what the thing can be exchanged for - aka price).

Much of mainstream economics reduces the broad philosophical concept of value to the narrow economic concept of exchange-value or price.

And it's not warm and fuzzy: what's the "value" of an unpolluted atmosphere? What's the value of good health? These things generally defy attempts to be priced (though what attempts have been made are risible), yet are fundamental - perhaps even more so than money - to a decent human existence.

In no way is the value of an unpolluted atmosphere or good health some abstract concept. They have a value. The point of putting a dollar figure on it is for comparison purposes.

You may disagree with the value placed on these things, or perhaps value them differently than "the average", but don't assume that their value can't be calculated.

Economists and policy makers don't know how to calculate the monetary value of a clean atmosphere, nor do they know who should pay for it or how. So when making decisions they quietly assume the value is zero. We would be better off if they assumed the value was infinite.

There are plenty of ways to calculate the value of a clean atmosphere, though I agree that a good calculation is difficult, and the question of who should pay for it and how isn't easy either (but more of an ethics-politics question than the value itself).

I disagree that we'd be better off if they assumed the value was infinite. Under that calculus, anything that might possibly impact the atmosphere would be banned: things like energy generation of nearly any form, which most reasonable people would agree is of positive benefit.

There is a value to it, that value is hard to calculate, but unfortunately, 0 is much closer to the real value than infinity.

> Why are feet and miles the metric of distance.

Sorry to be glib, but as someone who lives with a sane system of units and measurements, I can't help but point out the irony of your statement.

I'm in England, but assumed I was replying to an American.

But that's not the same thing, value is by definition subjective, and price does not express my valuation or your valuation of the items traded, it just expresses the intersection of supply/demand curve. Value provided by antibiotics is enormous and yet antibiotics are cheap. If we created a law saying that I have a legal monopoly on all antibiotics sales for the next 20 years, the price of antibiotics would go up but it's value/utility wouldn't have to change - we don't need to quantify that statement to evaluate it. It's still very high on your marginal utility list, so you pay more. And the GDP was "increased" (assuming the money spent was from savings/loan that wouldn't be spent in the time measured otherwise) but you aren't any richer, only the producer is, and he got rewarded for monopolistic pricing. Profit is a good incentive when the producer corrected the resource allocation to take capital to a more productive use under the market rules, but it can be perverted if you don't have competition putting pressure, have rent seeking or don't account for negative externalities.