INTELLIGENT DESIGN EVIDENCE
General Evidence: Homology
General Evidence: Homology
Comparative anatomy of many living beings shows similarity in morphology,
i.e., in body parts and structure. Sometimes refered to as an organism's
Bauplan, which is a German word coined to refer to the "building plan" or
"blueprint" of the organism, common or "homologous" morphological
features such as skeletal frameworks point to a common intelligent designer.

Just as modern architects use blueprints having common building features
and engineers use common parts in different models of machines, it is not
surprising that an intelligent designer of living beings would use common
structure across various "models" of animals. In fact, it would be surprising
if that were not the case.
Without a "rule" (of scientific naturalism) that prohibits a scientific inference of
intelligent causation, common homology among various organisms would be
plainly and simply clear evidence of intelligent design. As Jonathan Wells and
Paul Nelson explain in their essay, Homology, a Concept in Crisis:

    "Before Darwin, homology was defined morphologically and explained by
    reference to ideal archetypes -- that is, to intelligent design."

It is only when unintelligent causes are mandated that common morphological
features are "proof" of unintelligent Darwinian descent with modification. Wells
and Nelson continue:

    Darwin reformulated biology in naturalistic[1] rather than teleological
    terms, and explained homology as the result of descent with modification
    from a common ancestor. Descent with modification, however, renders
    design unnecessary only if it is due entirely to naturalistic mechanisms.
    Two such mechanisms have been proposed, genetic programs and
    developmental pathways, but neither one fits the evidence. Without an
    empirically demonstrated naturalistic mechanism to account for
    homology, design remains a possibility which can only be excluded on the
    basis of questionable philosophical assumptions.

Wells and Nelson continue:

    Diverse organisms possess homologous features. Homology in some
    cases may or may not be due to inheritance from a common ancestor, but
    it is definitely not due to similarity of genes or similarity of developmental
    pathways. In 1971, Gavin de Beer wrote: "What mechanism can it be that
    results in the production of homologous organs, the same 'patterns', in
    spite of their not being controlled by the same genes? I asked this
    question in 1938, and it has not been answered." (de Beer, 1971, p.16)
    Twenty-six years later, the question still has not been answered.

    Without a naturalistic mechanism to account for homology, however,
    Darwinian evolution cannot claim to have demonstrated scientifically that
    living things are undesigned, and the possibility remains that homologies
    are patterned after non-material archetypes. Without a demonstrated
    mechanism, naturalistic biologists are left with only one alternative:
    exclude design a priori, on philosophical grounds.

    This exclusion could be taken as a statement that intelligent design does
    not exist, or it could be taken as a statement that intelligent design is
    beyond the reach of empirical science. The first is a philosophical or
    theological statement, and warrants the same response. The second is a
    methodological limitation which cannot be logically extrapolated to a
    limitation on reality. In other words, a scientist who makes the first move is
    engaging in metaphysical disputation, while a scientist who makes the
    second is declining to investigate a possible aspect of reality.

    Unfortunately, many biologists make both moves, but fail to distinguish
    logically between them. While justifying their exclusion of intelligent
    design on methodological grounds, they act as though science has
    disproved its existence by providing a naturalistic explanation for
    homology. When confronted with the fact that science has failed in this
    regard, they reaffirm their methodological commitment and express faith
    that a naturalistic mechanism will someday be discovered.

In the end, Wells and Nelson contend that genetics and developmental pathways
are insufficient unintelligent causal agents to account for common morphology.

FOOTNOTES:

[1] In this article, "naturalism" and "naturalistic" refer to the philosophical doctrine that nature
is the whole of reality, and that intelligent causation does not qualify as a scientific
explanation.