If we had to synthesize the approaches that have been proposed so far to explain the presence of criticality spreading over such a wide range of natural systems, we could broadly consider two general positions. On the one hand, we find approaches assuming that biological systems are self-tuned, either by learning or evolution, to regions of the parameter space displaying optimal fitness, and that these optimal points are often placed near critical points due to the functional advantages of critical behaviour3,12. In other words, criticality is understood as a by-product derived from the adaptive or survival processes of living systems. On the other hand, we find different views focused on the idea of self-organized criticality systems (SOC), in which criticality emerges spontaneously from simple local interactions, without fine tuning of the parameters of the model. Typically, SOC models exploit clever local rules (e.g. in cellular automata) that produce critical behaviour in a specific context13–15.