Fungibility is a measure of substitutibility. The more things are fungible, the more the market is a proper mechanism for allocation. The less fungibility in the system, the less effectively markets serve as allocators.
Fungibility is the opposite of particularity.
Inalienability in the production process – what we might call craftsmanship – is a measure of the lack of fungibility in the production of one unit relative to the production of the next unit.