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Psy-Kosh comments on Reductionism - Less Wrong

40 Post author: Eliezer_Yudkowsky 16 March 2008 06:26AM

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Comment author: Psy-Kosh 02 January 2009 08:04:54AM 2 points [-]

Wockyman: It's not that they're the smallest, as such.

Yes, how a particle acts is affected by those around it. But the idea is that if you know the basic rules, then knowing those rules, plus which particles are where around it lets you predict, in principle, given sufficient computational power, stuff about how it will act. In other words, the complicated stuff that emerges arises _from_ the more basic stuff.

Think of it this way: You know cellular automatons? Especially Conaway's Game of Life? Really simple rules, just the grid, cells that can be on and off, and basic rules for when a transition occurs based on a cell's and its neighbor's state.

Yet complicated behavior arises out of that. One would not, however, say that behavior is beyond the rules, or that reduction to those rules fails. Those complicated behaviors arise out of those simple rules.

Incidentally, if you looked through Eliezer's QM sequence, the more fundamental reduction isn't so much particles, but probably quantum amplitudes over configuration space, with particles corresponding with it being possible to "factor out" certain sets of dimensions in the configuration space.

(Reductionism does _NOT_ mean "reduction to particles", just "reduction to simple principles that are the basic thing that give rise to everything else", not identical to, but similar to the way that comparatively simple rules of chess give rise to really complex strategies (and even more so for Go))

As for it being "just a map"... it is a map, but it's a map about something. The map may not be the territory, but there is a territory, and the fact that the map seems to tell us accurate stuff about the territory is at least a justification for suspecting that the actual underlying reality of the territory may actually resemble what the map claims it's like.