The new sciences of chaos and complexity render such critiques of limited scope. The geometry of actually existing 'structures' do not fit the tight and tidy models of structures such that boundaries can be clearly drawn, cases assigned unambiguously and correlations derived which are always and everywhere valid. Process may or may not become structure 2. Structure becomes ever more fuzzy and difficult to locate as social dynamics become ever more complex. New techniques from physics and mathematics allow us to locate 'hidden' structures in complex social data sets.
Structures have a euclidean geometry.
Such views tend to be nihilistic, simplistic, reductionist reifications of a much more complex process most resistent to research. Complex societies may have four, eight, sixteen or more class strata, each more difficult to discover using modern techniques of measurement and inference. Causality of class emerges as 'entrainment' develops. The boundaries of class structures become qualitatively less clear, precise, or discernible with each additional bifurcation. Classes and class structures may continue to exist and continue to have 'causal efficacy' even in very complex social dynamics.