Evolution’s Limits – Are Cars Evolvable?

Car evolution...proves no intelligent design

This is part of a series: Evolution’s Limits
Previous: Evolution’s Limits – Do Bolts Make Engines Evolvable?
Next: Evolution’s Limits – My Definition of Irreducible Complexity

What do cars have to do with evolution’s limit?  They’re an interesting corner case that Michael Behe’s original definition didn’t catch.

I might have figured out how to test in a lab for the limit of evolution (irreducible complexity), and I’m reading up on the subject to find out if my idea will work.  The first thing I need to do is make sure that my definition of evolution’s limit is good enough for what I want to do.  I’m also debunking some objections that people have raised to the argument that life is too complicated to appear by evolution.

Today, I’ll explain a technicality that I thought of in Behe’s original definition, and give an improved version.  It turns out that William Dembski – a big name in the intelligent design movement – thought of this more than 10 years ago.

I’ll start with Behe’s original definition:

“By irreducibly complex, I mean a single system composed of several, well-matched, interacting parts that contribute to the basic function, wherein the removal of any one of the parts causes the system to effectively cease functioning”.  (Michael Behe; Darwin’s Black Box; page 39)

Basically, if something can’t appear one mutation at a time, with each mutation giving a big improvement over the last step, it pretty much can’t appear by evolution.  He said that the way you could test if something is irreducibly complex is with a knockout test – knock out each part, one at a time, and see if the machine will still work without one of them.

But what about cars?  Think about it:

  • I can pull some parts off a car – like the speakers or mirrors – and it’ll still drive.  But…
  • I’m pretty sure that it’s impossible to evolve a car in a biologically realistic way.

Behe’s original definition of evolution’s limit was flawed.  There are some things that clearly are unevolvable, but pass his knockout test.

If I’m going to test for evolution’s limit, I need a better definition.

A few years later, Dembski addressed this.  Here’s his improved definition:

“A system performing a given basic function is irreducibly complex if it includes a set of well-matched, mutually interacting, nonarbitrarily individuated parts such that each part in the set is indispensable to maintaining the system’s basic, and therefore original, function. The set of these indispensable parts is known as the irreducible core of the system.” (William Dembski; No Free Lunch; page 285, 2001)

In short, as long as you can’t keep doing the knockout test until you’ve turned a human back into the first proto-cell, we’re still unevolvable.

There’s still some room for improvement here, since evolution doesn’t invent fully-formed parts from scratch.  Instead, it builds them up one mutation at a time.  For what I want to do, I want a definition written in terms of mutations.  But I’ll leave that for another post.

This is part of a series: Evolution’s Limits
Previous: Evolution’s Limits – Do Bolts Make Engines Evolvable?
Next: Evolution’s Limits – My Definition of Irreducible Complexity

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