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|Does Irreducible Complexity Imply Bad Design?
Mar 20, 2006
This letter is about my objetions about Mark Perahk's article "Does Irreducible Complexity Imply Intelligent Design" that appeared on the Skeptical Inquirer, which seems to be similar to "Beyond suboptimality: Why irreducible complexity does not imply intelligent design".
I'have already discussed this with Mark but I think that our discussion come to a stale, so I'm posting here to get other opinions.
In his article Perahk claims that any designed IC system is poorly designed, so if living systems are IC and designed, they are and example of bad design.
His reasoning can be formalized as:
All IC systems are vulnerable to damage.
All designed system vulnerable to damage are poorly designed.
Thus, all designed IC systems are poorly designed.
I think that this argument is unsound because the second premiss is false.
First, IC systems can be parts a of larger, non-IC system.
If such a system has a set of IC parts (or "sub-systems" if you prefer) which perform the same function, it can withstand the loss of one of the part because its function is replaced by another one.
While each part is IC and hence doesn't have redundancy, There can be a redundant amount of IC parts in the larger system, making it robust against damage.
For example, many machines contain screws.
Let's assume that screws are IC. If a screw is broken, it doesn't perform its function (of holding pieces together) anymore, but since machines usualy contain a redundant number of screws, the failure of one of them does't break the machine.
Screws are designed systems. They are IC, or at least they are vulnerable to damage. But this doesn't make them poorly designed.
This makes the second premiss of the syllogism stated above false. (Since it's a categorical premiss, a single counterexample proves its falsity).
Similarly, living cells may be examples of non-IC systems containing a lot of IC subsystems which exist in many copies.
(Maybe ribosomes or ribosomal sub-units can be an example of IC subsystem that exists in many copies).
Also, note that even a designed IC system that exists in a single copy so its function can't be replaced can be well-designed.
In fact, engineering is all about trade-offs between different desiderable qualities.
While redundancy is a desiderable quality, it conflicts with other ones like low energy consumption, low raw materials needs, etc.
So engineers, while entailing some redundancy, cannot duplicate every system's function.
For instance, cars usually have a single crankshaft in their engines. If it breaks the car stops working. This is obviously a lack of redundancy, but doesn't make the car poorly designed.
As an example of an IC system whose function cannot be replaced, Perahk offered the blood clotting system (probabily quoting Behe).
Beyond suboptimality: Why irreducible complexity does not imply intelligent design