What are the problems with reductionism?

Question

It seems intuitive to me to think that if there is a basic substance or building block of nature (e.g. fermions and leptons, etc.), then all facts regarding entities comprised of that substance are reducible into facts about instances of said substance. For example, the term "water" is reducible, on a chemical level, to "two hydrogen atoms combined with an oxygen atom via covalent bonds." In turn, this chemical equivalent of "water" is reducible to something like "two sets of identical combinations of subatomic particles combined with another unique combination of subatomic particles via [insert some atomic description of covalent bonds] (I'm no physicist)." I like to think that this process can proceed until we reach the most basic of substances, at which point we would arrive at the most primal description of a phenomena.

I think topics of the social sciences are subject to this as well. For instance, "a language" can be reduced to "particular sets of certain reverberations used in certain groups of massive collections of subatomic particles (people) who engage in brain states that correlate both/either artifacts of physical substance and/or brain states with some of those particular reverberations of sound." Obviously, you could go "deeper" in the analysis, but for the sake of time and my sanity, I won't try to do any better; you probably get the idea.

That was just my understanding of a typical reductionist project, but I have a feeling that I might have just conflated reductionism with physicalism. My question still stands, regardless: What are some of the problems with reducing natural and social phenomena into facts about the primary substance of which they are all ultimately made of?

Answer 1

For emergentists, the problem with reductionism is not in theorizing the reduction, it is in imagining that you can understand the original by looking at the reduced form.

You can easily reduce all of life to chemistry, but you will fail to understand reproduction or other goal-driven behaviors. The concept of the will to survive probably has a hormonal analog, but by focussing on the chemistry you would forever fail to notice that it existed.

So by writing off the relevance of all the intermediate layers as places where we need conceptual anchors, and insisting that the most basic explanation is 'better' than others, reductivists lose sight of the real question: What is and is not an explanation? A theoretical reduction fails to be an explanation if it raises the complexity so fast that it does not make anything plainer.

By training I am partially a Jungian, so I fully acknowledge that God talk is probably reducible to a social convention (an Archetype of the Collective Unconscious) which is reducible to individual mental models, which are reducible to neurology, then to biology, to chemistry, to physics... But that does not mean that God is just physics and it is pointless to discuss the Godhead, unreduced, at the top level, unanalyzed. Our collective intuitions of perfection, transcendence and 'meaningfulness' get expressed in multiple ways on multiple levels. But reductivists want to discard the top level, or declare it pointless, simply because it has a lower-level causes.

The most compelling model of the world is not going to be the one that is expressed at the finest level of granularity, it is going to be the one that reduces complexity most efficiently at each level of reality without escaping or denying higher or lower ones.

Answer 2

The Complete Works of William Shakespeare is reducible to the same set of letters, spaces and punctuation marks as The Complete Tweets of Paris Hilton. No understanding of those fundamental letters explains the difference between the two. The meaning emerges at a higher level of organization, it is embodied at the lowest level but not explained by it.

Is it reasonable to say all facts about The Complete Works of William Shakespeare are reducible to facts about the letters that compose that work? We can describe the letters in enough detail that the book can be reproduced. But is a fact about the impact or the artistry of Shakespeare really reducible to any fact (no matter how complex) about the letters composing Shakespeare's works?

Answer 3

Many social phenomena demonstrate gestalt behaviors, where the behavior of the whole is different from the sum of the behaviors of the parts. Reductionism makes it very tempting to ignore these effects, and quite often you find you are left with nothing.

In theory, if the world did indeed derive all state from some primary substance, as reductionism suggests, it would be possible to capture this gestalt behavior simply by measuring the state of everything at that primary substance level, and then simulating it. However, in practice, this measurement is not attainable. The measurements at this level are constantly fluctuating in real time, and it can be neigh impossible to capture the gestalt behavior unless you can freeze time. Thus, even if reductionism is true, it can still be an ineffective tool for exploring the world around us.

Answer 4

Reductionism, which understands higher order descriptions in terms of lower order descriptions, can't be understood without Emergentism - how higher order descriptions arise from lower order descriptions.

This is the movement, for example, that is described in Hegels Logic.

Or for example, the bulk properties of matter from microscopic ones, which is described by statistical mechanics.

Answer 5

I think the easiest to understand refutation of reductionism involves fractals.

There is a well known fractal that can be generated by folding a piece of paper. If you take a long strip of paper, fold it in half, and then in half again (always folding the same direction), and keep on doing so, then (if it were physically possible to make sure every crease was sharp) the shape that the paper would take, viewed edge on, when you unfold it partially so that every crease now is a 90 angle, is called the dragon fractal. Below is the fractal that would be generated if you could fold it just 13 times:

The description of the paper folding is one reductionist description of the fractal, but it tells us almost nothing of real interest about the final shape --its complexity, elegance, or overall shape. Those all emerge at a higher level than available at the level of basic description of how to generate the fractal. It's hard to justify saying that all the facts about the fractal are reducible to facts about how the paper was folded, especially since the same higher order pattern can emerge from any number of radically different foundations --for example, it's also the path with the rights and lefts generated by translating rings removed to "rights" and rings put on to "lefts" when solving a puzzle involving removing a "key" made from a wire loop from a set of linked rings. In theory it is as entirely reducible to that solution as it is to the strip of paper, but it what sense does either reduction explain the fractal?