Irreducible Complexity Pwned

More than two hundred years ago, there was a theologian called William Paley. One day, he looked at a brass watch and thought: "Hmm... brass watches are really complex things, with so many parts that must fit together perfectly in order for them to tell the time properly."

Then, he had a flash of insight: "Hey, living things are complex things too! In comparison to a watch, a human being contains way, way more parts. All these parts must fit together perfectly in order for a person to be alive."

"In fact, living organisms must be separately constructed in their own unique way. Since brass watches are made by smart people, living things must be made by an even smarter 'person', why, this is the ultimate proof of the existence of an intelligent, Designer God!"

Thus, the Watchmaker Analogy was born.

Fifty years later, Charles Darwin came along and proposed that all life on Earth is linked. Modern living organisms are not specially created - they descended from organisms that lived in the past. Over millions of years, descendants of a common ancestor can change so radically that they diverge into different species of living things. This explains the wonderful diversity of life on our planet.

Darwin's idea had been controversial from day one, but today, after almost 150 years of research work by thousands of scientists, from a variety of fields using different approaches, the theory of evolution by natural selection has been validated as scientific fact. Although many details of this process are still unclear (that's where I come in), most scientists agree that evolution itself is strongly supported by evidence.

Of course, there are a few exceptions. In 1996, biochemist Michael Behe published a book called "Darwin's Black Box", where he introduced the concept of irreducible complexity - essentially reviving Paley's argument about a Designer God.

Instead of a brass watch, he used the analogy of a mousetrap. He believed that all the parts of a mousetrap must fit together for it to work properly. He then extends this to the idea that many structures inside the cell are irreducibly complex and must be precisely made by a Designer God.

Unfortunately, he chose a poor analogy. His critics managed to make mousetraps using fewer and fewer parts than he could ever imagine. Worse, they even demonstrated that a complex mousetrap can be modified from simpler "ancestors".

Due to this and many other reasons, irreducible complexity is not a hypothesis that is taken seriously by most scientists. However, opponents of evolution relentlessly repeat this idea as if it is a major blow to evolutionary biology.

Now that I've given you a brief background on this debate, let me tell you what I think.

To be fair to Dr. Behe, neither the brass watch nor the mousetrap are good analogies to living organisms. I'll demonstrate this fact to you, but I won't compare and contrast all the details between single-function machines like the watch and living systems.

Fresh Brainz isn't like those other science blogs!

Instead I will give you a super simple example why irreducible complexity is utter bunk.

Think of a baby. Coochy-cooch-coo!

Babies are complex organisms, yes? They grow and grow. Different parts of the baby grow at different rates. By the time they become adults, the proportion of their body parts have become quite different.

Can a watch grow like this? Nope. If the gears or the brass casing grows proportionally faster, the entire watch fails. Similarly a mousetrap.

Living systems are not rigid like a watch, they are flexible and robust. They have a modular organization, that allows for variation in some parts not to affect the function of other parts. This same feature also permits the organism to evolve. All the parts don't have to be perfect - what about people with extra fingers? Or people with organs on the "wrong" side of the body?

The overall organization is more important than the precise position of every cell in the body. In fact, due to the constant turn-over of cells, you may be a "different" person from year-to-year! In addition, we lose thousands of nerve cells from our brainz everyday. How can we even remember what just happened with so many missing parts?

Where was I?

Oh yes, as I was saying, if a baby was really made up of perfectly-aligned components, then growth would be impossible. Any tiny mis-timing in the growth of one part will cause all the other parts to fail.

A Designer God would have to make a brand new baby every time.

This is what irreducible complexity would predict.

And this is exactly what we don't observe.


To learn more about the evolution of complexity, I recommend "The Plausibility of Life" by Kirschner and Gerhart. It's a bit heavy, but overall an excellent read.