The fact that the Weibull size effect is a power law means that it is self-similar, i.e., no characteristic structure size D 0 exists, and l 0 and material inhomogeneities are negligible compared to D . This is the case for fatigue-embrittled metals or fine-grained ceramics except on the micrometer scale. The existence of a finite D 0 is a salient feature of the energetic size effect, discovered in 1984. This kind of size effect represents a transition between two power laws and is observed in brittle heterogenous materials, termed quasibrittle. These materials include concrete, fiber composites, rocks, coarse-grained and toughened ceramics, rigid foams, sea ice, dental ceramics, dentine, bone, biological shells, many bio- and bio-inspired materials, masonry, mortar, stiff cohesive soils, grouted soils, consolidated snow, wood, paper, carton, coal, cemented sands, etc. On the micro- or nano scale, all the brittle materials become quasibrittle, and thus must exhibit the energetic size effect.