Journal on Policy & Complex Systems Vol. 2, Issue 2, Fall 2015 | Page 105

Journal on Policy and Complex Systems
4 . Reactive Emergence

The preceding all involved direct effects . Indirect effects are often more important . Consider one of the simplest indirect effects : turning on a light by flipping a switch . The act of flipping a switch does not supply energy to the light source . All it does is enable a flow of electric current , which provides the energy that produces the light .

Should the light going on be considered an emergent phenomenon ? It does not satisfy the traditional definition of emergence : something “ arising ” from elements that are more fundamental . It is more a matter of redirecting — or in this case unblocking — an existing energy flow to produce a new effect . If we were not so familiar with this phenomenon , it would be quite surprising . Flip a switch , say , on a wall and light appears somewhere else in the room . Amazing ! Surprises like that are considered one of the hallmarks of emergence .
However , considering all redirections of energy as emergent is probably more than we want . Otherwise all computation becomes emergent . After all , the heart of a computer is the transistor , and the job of the transistor is to act as a switch , that is , to redirect energy flows .
When energy flows are redirected in the course of a computation , the redirection is both direct and intentional . Flipping a light switch also qualifies as direct and intentional redirections of an energy flow . What we want are cases in which energy flows are redirected in some sense intrinsically rather than directly .
Consider Gresham ’ s law again . Gresham ’ s law involves an indirect redirection of energy flows . The introduction of coins with the same face value but less intrinsic value than existing coins leads to the hoarding of coins with more intrinsic value and wider use of the new coins . Is this an emergent phenomenon ? It does not “ arise ” from elements that are more fundamental . It is not emergent in the traditional sense . 16 Yet like the light going on , Gresham ’ s law reflects a redirection of energy flows — the act of withdrawing certain coins from circulation . As such , it is reasonable to consider it an emergent phenomenon .
Since such phenomena frequently involve agents that behave differently because of a change to the environment , it makes sense to refer to it as reactive emergence . Thus , reactive emergence involves two elements : a change to the environment and an intrinsic ( often agent-mediated ) redirection of an energy flow . Some examples may help clarify the nature of this class of phenomena .
• A recent Supreme Court decision upheld the University of Texas approach to admitting students through both a “ top percentage ” plan and additional “ holistic ” considerations . In his majority opinion , Justice Anthony M . Kennedy ( 2016 ) quoted Justice Ruth Bader Ginsberg ’ s minority opinion in an earlier hearing to describe the unintended effect of the rule that
16 Since it does not originate from more fundamental elements , it is not clear why Papineau ( 2009 ), Pigliucci ( 2013 ), and O ’ Connor and Wong ( 2015 ) considered it even a candidate for emergence .
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