Discovered maybe, but certainly not invented.

This is actually debated. Check out DG’s book on the history of debt.

Don't even pretend that the market is some sort of natural phenomenon. That's got human fingerprints all over it

Of course, market is natural phenomenon. Every process with pressure, suction and or differences of potential is trying to achieve equilibrium. Electricity, hydraulics, they all manifest the same principles. Except that in nature, it's driven by pure physics. With people, you need to understand value and it's more generic. One step more generic from physics, is cybernetics. And market is a cybernetic system with difference of energies trying to achieve equilibrium.

Humans aren't a natural phenomenon?

Could you define "market" because I don't think you're using the word the way I would use it.

Markets exist in nature with the whole “seeking equilibrium” of so many natural systems (eg, chemical reactions).