  The "universality" of critical phenomena is much discussed in philosophy of
scientific explanation, idealizations and philosophy of physics. Lange and
Reutlinger recently opposed Batterman concerning the role of some deliberate
distortions in unifying a large class of phenomena, regardless of microscopic
constitution. They argue for an essential explanatory role for "commonalities"
rather than that of idealizations. Building on Batterman's insight, this
article aims to show that assessing the differences between the universality of
critical phenomena and two paradigmatic cases of "commonality strategy" - the
ideal gas model and the harmonic oscillator model-is necessary to avoid the
objections raised by Lange and Reutlinger. Taking these universal explanations
as benchmarks for critical phenomena reveals the importance of the different
roles played by analogies underlying the use of the models. A special
combination of physical and formal analogies allows one to explain the
epistemic autonomy of the universality of critical phenomena through an
explicative loop.
