Removing Bias From the Definition of Reductionism

post by RogerS · 2013-03-27T18:06:36.244Z · LW · GW · Legacy · 48 comments

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The test for an unbiased definition of a philosophical position is (surely) that it is equally acceptable to critics and defenders of the position. I think the definition of reductionism in the wiki blatantly fails this test. The same bias is apparent in the old Sequence posting dealing with reductionism. (Some comments called it a “straw man” without spelling out why.)

Consider the definition:-

Reductionism is a disbelief that the higher levels of simplified multilevel models are out there in the territory, that concepts constructed by mind in themselves play a role in the behaviour of reality. This doesn't contradict the notion that the concepts used in simplified multilevel models refer to the actual clusters of configurations of reality.

 

The unavoidable implication is that critics of reductionism believe that the higher levels of simplified multilevel models are out there in the territory.

Certainly, nobody but the flimsiest of straw men could possibly believe this, since all parts of the models are by definition not part of the territory: they are part of the map. It might be possible to believe, by contrast, that the territory actually has built into it things that correspond in some sense to higher levels of a hierarchical map, whether simplified or no; or that whether there are or are not such things is not decidable or meaningful; or one could believe that there are definitely no such things, that hierarchical higher levels of organisation (clusters) are meaningful only as mental artefacts.

The second disbelief, that concepts constructed by mind in themselves play a role in the behaviour of reality, also appears to be unimpeachable. However, by attaching this claim to the first claim, it is implied (without examination of the implication) that this statement only applies to the higher levels of simplified models. Yet logically, it cannot be confined to the higher levels but equally applies to the lowest level of the map: it is not the pixels of even the best possible map that themselves play a role in the behaviour of reality, but only something in some way corresponding to them.

In the Sequence discussion of reductionism we read:

So is the 747 made of something other than quarks?  No...

And bigjeff5 later comments

The territory is only quarks (or whatever quarks may be made of).

But baryons, which are part of the map, are made of quarks, which are therefore also part of the map. In fact they are the pixels of the best available map today. The map is not the territory. Therefore quarks are not part of the territory. So nothing is made of quarks except in our current map. To say that reality is made of quarks is an acceptable shorthand in many contexts, but in a discussion whose whole point is to emphasize the need not to confuse the map with the territory, disregarding the distinction at quark level is at least prima facie evidence of a biased approach!

TWO KINDS OF SIMPLIFIED MAPS

The wiki definition I began with includes the word simplified for reasons that are not clear. The Sequence discussion seems to me to confuse two different senses of the term: simplification by approximation and simplification by selection. Newton’s theory is now regarded as a simplified version of Special Relativity that serves as an excellent approximation in certain contexts. In this case the key is that the simplification is an approximation. Treating the forces on an aircraft wing at the aggregate level is leaving out internal details that per se do not affect the result. There will certainly be approximations involved, of course, but they don’t stem from the actual process of aggregation, which is essentially a matter of combining all the relevant force equations algebraically, eliminating internal forces, before solving them; rather than combining the calculated forces numerically. So is the definition addressing approximate maps or selective maps?

WHICH TERRITORY?

A question raised in the discussion but never answered as far as I can see is whether the belief referred to applies to our particular universe or to any universe one could conceive (so is more like a belief about the nature of explanation). While much of the discussion is focussed on our universe, various analogies advanced by commenters suggest that applicability to all universes is intended. I will assume the latter. A further confusion is that whereas the usual definition of reductionism refers to reduction of any system to its elements, and thus, for example, covers the reduction of lifeforms to their genetic recipes, the focus on “the territory” seems to confine the definition to physics: genes, being “made of quarks”, are just a level of the map.

DEFINITIONS

A definition that consists of disbelieving a contradiction in terms and then disguising a selective application of a truism, is clearly biased, and leads to apparently biased thinking, so I will attempt an unbiased definition.

Of course, we could simply import a definition from Wikipedia or elsewhere, but I am trying to capture the particular approach and terminology of this site (from initial impressions) in an unbiased way.

If I understand it correctly, reductionists on this site believe that, for the purposes of causal explanation, any “territory” in the sense of physical reality is best characterised as corresponding only to the lowest hierarchical level of our best map of it, higher levels of organisation existing only in the map. Is that right?

The summary in the SEQ_RERUN is also worth repeating:

We build models of the universe that have many different levels of description. But so far as anyone has been able to determine, the universe itself has only the single level of fundamental physics - reality doesn't explicitly compute protons, only quarks.

Which seems to mean much the same as my definition (if it means anything to say that “the universe computes”).

Psy-Kosh implicitly criticises the reference to quarks in claiming:

Reductionism does _NOT_ mean "reduction to particles", just "reduction to simple principles that are the basic thing that give rise to everything else".

But that doesn’t exclude “simple principles” that emerge from higher levels of organization, so doesn’t really fit the bill either.

The most relevant corresponding wording in Wikipedia is interesting because it makes no reference to the model/reality (map/territory) distinction which Eliezer seems to think makes ontological reductionism intelligible:

In a reductionist framework, [a phenomenon] that can be explained completely in terms of relations between other more fundamental phenomena  exerts no causal agency on the fundamental phenomena that explain it.

This assumes that the term “more fundamental” is defined, and (like my definition) doesn’t distinguish sequential causation from structural causation. Hmm, maybe this needs a separate post sometime.

FOOTNOTE: WHAT ABOUT THE HEURISTIC SENSE?

As Perplexed pointed out, the discussion of reductionism in the Sequences clearly refers to ontological reductionism by contrast with methodological reductionism. The same applies to the wiki definition and my proposed correction.

I entirely support this distinction. I am focussing here on ontological reductionism because so many contributors define themselves as “reductionist materialists” as a matter of belief. One would no more define oneself as a heuristic reductionist than one would define oneself as a hammer user (rather than a screwdriver user, say) as a matter of conviction.

TEASER

This quarrel about definition is not mere pedantry, since it hints at an unconscious bias. Moreover, if there are signs of agreement with this definition (or improved versions of it) and my newbie’s karma doesn’t suffer, I hope to build on this beginning to suggest that the real difference between proponents and supporters of ontological reductionism is that they are using two subtly different conceptions of what we mean by “the territory” and “the map”, both consistent with the definitions.  (Both conceptions have been implied by different contributors but without considering that the difference may be one of convention).

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