Workers of the world unite. He knew that ten thousand men could labor to build a pyramid and no one would pay anything for it. This was the paradox of value which no economist could resolve. Bohm-Bawerk knew that you and other consumers are the true arbiters of value. You choose whether an item has value to you.
Value is subjective.
If you have three wagon loads of grain to last you the winter and you plan to eat one load, use another for seed and feed the birds with the other, you would naturally price them differently. You would trade the third load for much less than the second. It's called marginal-utility. The Austrians solved the value paradox by stating that you don't value the entire world supply of an item, but only a given supply which you can use at that moment . This brilliant analysis became the accepted economic alternative to the value theory of Marxist economists and the core of Austrian economic theory.