  The observation of scaling in processes in which a weakly interacting probe
delivers large momentum ${\bf q}$ to a many-body system reflects the dominance
of incoherent scattering off target constituents. While a suitably defined
scaling function can provide rich information on the internal dynamics of the
target, in general its extraction from the measured cross section requires
careful consideration of the nature of the interaction driving the scattering
process. The analysis of deep inelastic electron-proton scattering in the
target rest frame within standard many-body theory naturally leads to the
emergence of a scaling function that, unlike the commonly used structure
functions $F_1$ and $F_2$, can be identified with the intrinsic proton
response. The implications for the theoretical analysis of deep inelastic
scattering and the interpretation of the data are discussed.
