We argue, in light of Collapse Model interpretation of quantum theory, that
the fundamental division between the quantum and classical behaviors is
analogous to the division of thermodynamic phases. A specific relationship
between the collapse parameter $(\lambda)$ and the collapse length scale
($r_C$) plays the role of the coexistence curve in usual thermodynamic phase
diagrams. We further claim that our functional relationship between $\lambda$
and $r_C$ is strongly supported by the existing IGEX collaboration data. This
result is preceded by a self-contained discussion of quantum measurement theory
and the Ghirardi-Rimini-Weber (GRW) model applied to the free wavepacket
dynamics.
