One of the major accomplishments in 20th century elementary particle physics was the identification of the u, d, s, c, b set of fractionally charged quark states. These quarks combine to accurately reproduce the isotopic spin states of a wide variety of particles, and they dominate the lifetimes of the longer-lived states. However, the quark mass values, and hence the mass values of the particles they create, remain a mystery.

Apart from the difficulties posed by the non-observability of individual quarks, there are three theoretical reasons for this impasse:

1. By failing to recognize that the weakly interacting leptons and strongly interacting hadrons share a common mass formalism, and by insisting on treating them as separate entities, elementary particle theorists have lost the hadron ground state.
2. By overlooking the well-documented scaling of long-lived particle lifetimes in powers of the fine structure constant , particle theorists have also overlooked an analogous scaling of particle masses.
3. By attempting to use the same u, d and s quark masses for both the low-mass pseudoscalar mesons and the higher-mass nucleons and hyperons, particle theorists have trapped themselves in the pseudo-world of current-mass quarks, as opposed to the empirically-suggested real world of constituent-mass quarks.