Clarifying Reductionism

More rough notes, written more for my benefit, as an aid to organising my thinking, than as a geninue attempt to convince anyone of anything. It's all for me me me -- it's not for you *.

As Richard Dawkins has noted, reductionism is uncool. Even the name has a negative tinge: it's reducing things to something less than the original.

It is one of those concepts that everyone thinks they understand, because it seems so simple and self-evident: reducing things to their parts. Except, this self-evident view is wrong.

It's describing what Stephen Weinberg has called petty reductionism. Reductionism proper, what Weinberg has called, grand reductionism (he has borrowed both 'petty' and 'grand' from the language of criminal law) is the view that reality is the result of fundamental, universal laws, and that all the systems and apparent 'layers' that we see are simply the results of the operations of these laws.

The following is a short list of the reasons, it seems, people make flawed arguments against reductionism:

• equating reductionism with -- the obviously wrong -- petty reductionsim
  • this is why people think that "emergence" and the "whole is greater than the sum of the parts" stuff shows reductionism is wrong. Note that unless you think that these things violate the laws of physics, then you don't think these things violate reductionism proper.
• equating reductionism with a methodology of trying to understand something by understanding its parts, and then using a failure in achieving this as evidence that reductionism (that is, 'grand reductionism') is false. Daniel Dennett has used the term "Greedy Reductionism" for when people use a reductionist methodology and paint an oversimplified picture of a phenomena.
• assuming that reductionism must mean reducing to some specific thing, and that if you can't reduce it to that, this shows that reductionism is wrong. There is, for example, a very prevalent belief that if reductionism were true then this would mean that human behaviour would simply be reducable to DNA.
• assuming that the explanation of a phenomena must have the same properties as the phenomena itself. that is, life must be living because it has some life force. or that water molecules must have 'wetness'. this makes it hard to see how something could have an explanation on a lower-level because this invariably seems to involve things that don't have these properties.
• similar line, thinking that because something seems very complex, that it couldn't possibly have a reductionistic explanation because you can't see how that'd be possible. Why should people expect that they could forsee one?

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[*] which I came across via Scott McCloud (to find the specific spot on this page, search within the page for "Penny Arcade")