OK, I have to come back to reductionism. It’s like a sore in your mouth that you just have to keep touching.

I’m reading this book “Darwin Loves You” by George Levine. He at first gives a decent account of reductionism and its power. Then he goes into the most bizarre straw man argument. Honestly, I can’t find an argument against reductionism that isn’t a straw man (or perhaps I’m just not smart enough to see the error of my ways – please help me!)

Levine quotes a philosopher of science named John Dupre. According to Levine, Dupre says, “as objects are united into integrated wholes they acquire new properties.” OK, I’ve no problem with that statement, nor I believe would anyone calling herself a reductionist.

Then Dupre makes the further wild-eyed claim that “these higher-level wholes . . . have causal properties just as real as those of the lower-level wholes out of which they are constructed.”

Wow. So much for reductionism.

I honestly, completely, utterly don’t get it. Someone please help.

No one would ever deny that new properties appear as objects are united. Look around! A single water molecule displays no sense of being wet, but a mole of water molecules suddenly displays wetness. Of course they do (it does?). But surely no one would claim that this “new” property arises from some new law of nature? “Wet” is a property of hydrogen bonds, the fact that the loose hydrogens on every water molecule are attracted to all sorts of other things, resulting in the sticky adhesion that we call wet. That property doesn’t suddenly appear when we put a million, or a billion, or a mole of water molecules together. It was there from the start. That’s all reductionism says.

As for the second point (what little sense I can make of it), once “wet” is established, it can cause lots of other things – presumably things like the squishiness of bread or the slickness of concrete or the stickiness of flour once these things get “wet.” And again, surely no one is claiming a new law of physics for bread dough? Surely squishiness, slickness, and stickiness, all caused by the emergent property of wetness, are best explained by the same hydrogen bonding that makes water wet in the first place?

I understand that as a practical matter reductionism doesn’t always work. Even within physics this is well recognized. My own physics professor used the example of fluid flow. One could try to describe a flowing fluid as a combination of all the positions, all the momenta, and all the physical properties of the flowing particles. But the exercise is hopeless in its complexity. So physicists create a macroscopic object called the body of water (or whatever fluid) and describe it with properties – surface tension, adhesion, cohesion – that “emerge” within the fluid.

This approach has a chance of working. It can’t describe the motion of an individual molecule, but it can capture the motion of the fluid body. And yet surely no one using these simplifications imagines them to be real? Surely everyone recognizes that this is a shortcut, designed to make an impossible problem soluble? Surely no one believes that surface tension, adhesion, and cohesion are anything more than the collective actions of lots and lots of itty bitty molecules?

I know this topic doesn’t have the heat of an evolution vs creation debate. To me, though, the fuzzy thinking I see associated with “holistic science” is a bigger threat than all the young earth creationists you can shove in an ark.

Any thoughts on why this reductionism bashing has become so popular (particularly with, I’m sorry to say, the political left – where I find myself on most every other issue), yet (at least to my undiscerning eye) to be so utterly bereft of substance? Anyone? Bueller?

Advertisements