Scale exhibits regularities that transcend domain. Geoffrey West's scaling laws demonstrate that cities and organisms share metabolic exponents despite radical differences in composition—energy use scales with mass to the three-quarter power whether the system is a mouse or a metropolis. Albert-László Barabási's network science reveals the universal topologies underlying social, technological and biological systems: power-law degree distributions, small-world properties, preferential attachment. The Proportional Scale Index (PSI) emerges from this tradition as a metric designed to measure relational invariance across heterogeneous aesthetic phenomena—not to reduce complexity but to reveal the structural constraints within which variation occurs. Infrastructure Studies supplies the material systems to which PSI applies, from urban networks to archival distributions. Science and Technology Studies ensures attention to the situated practices that generate scalable patterns, preventing metric from becoming dogma.
