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“It suddenly struck me that that tiny pea, pretty and blue, was the Earth. I put up my thumb and shut one eye, and my thumb blotted out the planet Earth. I didn't feel like a giant. I felt very, very small.” – Neil Armstrong (1930-2012)

Fresh Reads from the Science 'o sphere!

Sunday, October 08, 2006

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.


Anonymous said...

Damn straight.

Xisla said...


William said...

Well done!

Anonymous said...

Sorry I don't have an account.

But I must say...I disagree with your argument. There are those of us out there (not a small number) who feel that evolution and creation are not necessarily contradictory ideas. I would like to see your take on the "evolution as a tool of God" theory.

ah said...

to anon 12:15:00

God is omnipitent - as soon as god created the universe he knew its exact evolution. all of time would be lain before him (or her).

So, for all intents and purposes god becomes irrelevant.

Hmm... Looking forward to the new Richard Dawkins book. Think I may have to push it on some of my christian friends to see just how strong their faith really is....

laurie said...

Nice essay! Great points, easy to read, and funny. Laurie

The Realm of The Realm said...

Well said!

The "God is [tautology of the day]" crowd always miss the pantheistic angle ...

How about this:

The baby IS also god, and as god expressed in and through the baby god IS making a brand new baby every time.

Of course, we cannot see that, because causal chains cannot be observed, only inferred.

The idiocy of the ID crowd is that credible evidence of ID would undermine their own compulsive (delusional?) beliefs.

If it's fun to watch a dog chase its tail, then seeing it catch it is hilarity in comparison. (Quick: which "it" in this paragraph would be governed by the theory of Intelligent Design?)

Can there be any credible evidence outside of "science"? Perhaps. "Science" is a social enterprise with all of the limits thereto appertaining.

"Believing in" science is as superstituous as "believing in" religion, or intelligent design.

Joe Rotger said...

I guess it's never too late.
Lim, the fundamental issue of the irreducibly complex argument is precisely that there is such an element which cannot be taken apart and continue to function with its original purpose.
It's the creationist marveling at the snapshot of life, versus the Darwinian movie trailer...
Unfortunately, your argumentation leads in the wrong and opposite direction. A baby is wonderful, or any living organism for that matter, it's so much more ...complex.
Behe, in his flawed attempt to prove evolution wrong, attacked evolution stating that there are these components in living beings which cannot be made of simpler components. He was proven wrong many times over. You can google the details yourself.
I can only add that the fundamental issue still stands. Dawkins himself says that he cannot prove God's nonexistence --as well as flying pots around the moon...
But the issue goes deeper. At this point, I recommend visiting the Greek philosophers, or philosophy (or metaphysics) in general.
In essence evolution explains life; there is no doubt in my mind.
But, before life... before the big bangs... at the beginning... what? And, at the end, won't we all be gods?
As one of the greeks said: the taught bow which holds the arrow is in tension at the beggining, then this tension allows the arrow to travel to its destination. Energy is transformed into change.
Heidegger adds: science is theology. What separates us from God is knowledge, the more we know, the closer we are to God.
There's a lot more to it. I'm talking out of my head...
In any case, I congratulate you for bringing up such an interesting subject to the table. I assume you will continue to visit it throughout your life. Best wishes.
P.S. I am writing about this subject in my blog --that's how I ran into yours-- un (or) fortunately, it's in spanish.

Lim Leng Hiong said...

To Joe,

I'm glad we agree that irreducible complexity is nonsense. A baby is indeed very complex, but he/she developed from just one cell. It's not magic, it's a biological process.

People who believe in irreducible complexity should then also believe that every human has to start from a tiny homunculi in the sperm - a popular belief in the 1700s.

But they don't.

If human beings can develop from just one cell why can't complex life evolve from unicellular ancestors?

As for your interesting discussion about theistic evolution, I will address it in a future post.

Thanks for visiting!

Mark said...

But the cell that the baby came from is a very complicated molecular machine, not to mention the DNA that every cell holds is a sophisticated library to collectively construct all the proteins that the baby's body will ever need to develop and function. How did those things form from dead chemicals? Even if intelligent humans tried to build a living cell and write DNA code from scratch, they would not be able to, much less would random chance or natural selection.

A better analogy for the baby is a computer server (the baby is more complex still). Computer servers are made of highly-engineered racks of processing and memory chips, intricate signal connections, power supply and device software written to run the whole thing. All of these components require intelligence to build (especially the programs written to run the hardware). You can't take out any of the fundamental pieces altogether or it won't work the way it's meant to. You will always need the signal connections, the processing chip, the storage, and the power source. If you want the server to grow and be more capable, you add more chips, memory, update the software, etc.

Is there anyone who can explain how cells gradually formed from inanimate material?

On my side, i can assert that we need intelligence to build something as complex as a human being. The same way we know that a computer server could not have built or programmed itself without any intelligent intervention at all.

Lim Leng Hiong said...

Hi Mark,

I'm glad you found my baby analogy problematic; I hope you see that illustrative analogies sometimes do not lead us closer to the truth. It is best to focus on the subject at hand.

Indeed, just as you don't agree with my baby analogy, so I don't agree with your computer server analogy, which depart from living systems in numerous critical areas.

Computer servers do not "grow" in the same sense as living systems, they do not reproduce themselves and they do not have descent with modification.

However, computer servers do exhibit some modular organization, and you are aware of this characteristic since you state that:

"You can't take out any of the fundamental pieces altogether or it won't work the way it's meant to."

This means that there are also many "non-fundamental pieces" in the computer server, which CAN be replaced or removed without causing the collapse of the overall system.

Which is precisely my point about the mechanical watch - if such a watch was used as analogy for computers, one would predict that computers will NEVER have hot-swappable components.

"On my side, i can assert that we need intelligence to build something as complex as a human being. The same way we know that a computer server could not have built or programmed itself without any intelligent intervention at all."

Without going into a long discussion about the definition of "intelligence" I would say that the evolution of any living system is not due to it "building itself" but is a confluence of both internal factors (such as mutation), external factors (such as natural selection) and chance events.

Thus, it is possible to consider the entire biosphere as some sort of emergent "intelligence" that is responsible for the appearance of human beings.

I guess our disagreement is that you believe that evolutionary dynamics must include supernatural explanations, whereas the evidence indicates to me that natural explanations are fully adequate.

Anonymous said...

Bull crap! The theory of irreducible complexity says that things are too complex to have come into being through random processes. It doesn't say anything about the growing part because that is not something that relates to the irreducible complexity theory. You intentionally chose the collapsed example (mousetraps) of irreducible complexity because someone else had already done the thinking for you. How about having a go at the bacterial flagellum and see how that goes?

Lim Leng Hiong said...

To Anon 4:29,

The use of the bacterial flagellum as an example of irreducible complexity has been discredited numerous times. It is deeply unconvincing to continue beating this very dead horse.

For others who are interested in this topic, here are two quick video intros:

The Evolution of the Flagellum

Ken Miller on Bacterial Flagellum