Fait-divers on emergence by David Chalmers

"We can say that a high-level phenomenon is strongly emergent with respect to a low-level domain when truths concerning that phenomenon are not deducible even in principle from truths in the low-level domain. Strong emergence is the notion of emergence that is most common in philosophical discussion of emergence, and is the notion invoked by the "British emergentists" of the 1920s. We can say that a high-level phenomenon is weakly emergent with respect to a low-level domain when truths concerning that phenomenon are unexpected given the principles governing the low-level domain. Weak emergence is the notion of emergence that is most common in recent scientific discussion of emergence, and is the notion that is typically invoked by proponents of emergence in complex systems theory." (David J. Chalmers)