Deffuant–Weisbuch model: randomly select pair (i,j). If |x_i − x_j| < ε, both move toward each other by μ: x_i ← x_i + μ(x_j−x_i). Large ε → consensus; small ε → many clusters. Expected clusters ≈ 1/(2ε). Bifurcation at ε≈0.5 between fragmentation and consensus.