The Paradox of Value — Adam Smith, 1776
"The things which have the greatest value in use have frequently little or no value in exchange... Nothing is more useful than water: but it will purchase scarce any thing... A diamond, on the contrary, has scarce any value in use; but a very great quantity of other goods may frequently be had in exchange for it."
Essential for life.
You'll die without it in 3 days.
Decorative sparkly rock.
Zero survival value.
Why do we pay almost nothing for something essential to life, but thousands for something purely decorative?
The solution lies in understanding the difference between these two concepts.
All the water in the world is worth more than all the diamonds
One more diamond is worth more than one more glass of water
Click a scenario to see how context changes everything:
Value isn't determined by total usefulness, but by the usefulness of the next unit. When water is abundant, one more glass adds little value. When diamonds are rare, one more adds a lot.
Each additional unit of a good provides less satisfaction than the previous one. Your first glass of water when thirsty: amazing. Your 100th glass today: worthless.
Price is determined at the margin where supply meets demand. Abundant water means supply exceeds demand at low prices. Scarce diamonds mean demand exceeds supply until prices rise.
Value is not intrinsic to objects—it exists in the minds of valuers. The same object can have different values to different people in different circumstances.
The diamond-water paradox was a key puzzle that classical economists couldn't solve. Its resolution through marginal utility theory in the 1870s launched the Neoclassical Revolution in economics, fundamentally changing how we understand value, price, and markets. Today, marginalism underpins virtually all modern economic theory.