Intelligent Design

Heuristic Value of Design vs Evolution

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An article entitled “Architectural Analysis and Intraoperative Measurements Demonstrate the Unique Design of the Multifidus Muscle for Lumbar Spine Stability,” in the current issue of the Journal of Bone and Joint Surgery, nicely refutes Dobzhansky’s pontifical pronouncement that “nothing in biology makes sense except in the light of evolution.”
The abstract is available online, though the full text article requires a subscription. This errant concept has been discussed previously on UD by DonaldM, but I thought it worth revisiting when I saw this example of the absolute lack of any usefulness of any concept of evolution in understanding at least this type of biological form and function.

The most striking thing about this article from a heuristic standpoint is that understanding the muscle under study depends completely on a design perspective, and owes nothing to any understanding of evolution. This is implicity acknowledged by the authors in the wording of their descriptions and conclusions:

“The architectural design … demonstrates that the multifidus muscle is uniquely designed as a stabilizer to produce large forces.”

From the discussion section:

“The large physiological cross-sectional area and relatively short fibers indicate that the multifidus muscle is architecturally designed to produce very large forces over a narrow range of lengths. This design allows the multifidus muscle to function more to stabilize the spine and less to provide motion of the spine.”

“The measurement of sacromere lengths in the present study permitted the discovery of a second important design feature of the multifidus muscle, specifically, that it is designed to operate on the ascending portion and plateau region of the sarcomere length-tension curve. The sarcomere length-tension curve is one of the classic structure-function relationships in all of biology.”(emphases added)

I am not quote mining here. The entire article implicitly supports and acknowledges the idea that the multifidus muscle is elegantly designed.
I do not mean to here suggest that the authors of this study meant it to support Intelligent Design. I do not know them and have no idea what their position is on ID. Quite likely their implied support for ID is unconscious.
However, there is no mention anywhere in the article of any sort of evolutionary story behind the “design” of this muscle, or of the classic relationship in all of biology of the sarcomere length-tension curve.

The investigators managed to come up with a hypothesis, conduct their study, and reach conclusions about this elegantly designed muscle without any consideration of or reference to evolution.

The multifidus muscle makes excellent sense purely from a design perspective, without bringing evolution into it at all. In fact, a design perspective is necessary to understanding the muscle’s architecture and function, specifically the elegant coordination of the fiber arrangements and locations of its bony insertions with the length-tension curve of the sarcomeres.
Any story-telling about the evolutionary origins of the multifidus muscle would be superfluous speculation adding nothing to our understanding of its form and function.

I think it would be fair to say that in this case at least, biology does not make sense except in the light of design.

4 Replies to “Heuristic Value of Design vs Evolution

  1. 1
    Domoman says:

    Sweet! So they don’t mention evolution at all? If so, that’s awesome! Nothing more annoying than the just-so stories often put into “science” articles.

  2. 2
    uoflcard says:

    You see, when the cavemen were running from sabertooth tigers, nature selected the genes of those that featured the most stable spines. It only appears to be designed.

  3. 3
    Joseph says:

    Kinesiology- the science I am currently studying- is all about muscles, bones and movement.

    The point being that EACH of the professors in that branch talk about the design of the body.

    So I pressed them- “Do you mean designed via natural selection or designed like an engineer would design?”

    Natural selction was laughed at.

    Where muscles attach to the bone is critical for functionality.

    Muscles have to attach above and below joints, and not just anywhere above and below will do.

    How muscles attach to bones and other muscles is also critical to functionality.

    Muscle to muscle requires ligaments. Muscle to bone requires tendons.

    Without these sturdier fibers muscle would be ripped off of bone and ripped apart from each other very easily.

    And how nerves allow for muscle contraction is also critical for functionality.

    Without the wet electricty provided by nerves muscles would not contract. And that electricity has to be controlled.

    But anway it was a very warm feeling to have my professors laugh at NS as a possible explanation for muscles.

  4. 4
    dacook says:

    Muscle to muscle requires ligaments.

    A small quibble: ligaments connect bone to bone.
    Muscles may indirectly connect to other muscles via fascia or shared tendons, but their direct connections are almost always via tendons to bone.
    The lumbrical muscles in the hand are an interesting exception: they arise from flexor tendons and insert into extensor tendons (lateral band and extensor hood; modified tendons)
    Even more interestingly, lumbricals in the foot differ from those in the hand in that they arise from tendon but insert into bone. This makes great sense from a design perspective because of the different function of fingers and toes; dexterity vs strength and balance.

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