In my previous post, we saw that Eugenie Koonin argued that a formal test of universal common ancestry (UCA) “is unlikely to be feasible” but yet he claimed that the evidence in support of UCA “by comparative genomics is overwhelming.” Such thinking is common among evolutionists, who seek to to demonstrate UCA by finding a consilience of multiple lines of evidence in favor of it. In his Nature paper, Douglas Theobald similarly seeks to support UCA through a consilience of multiple lines of evidence:

UCA is now supported by a wealth of evidence from many independent sources, including: (1) the agreement between phylogeny and biogeography; (2) the correspondence between phylogeny and the palaeontological record; (3) the existence of numerous predicted transitional fossils; (4) the hierarchical classification of morphological characteristics; (5) the marked similarities of biological structures with different functions (that is, homologies); and (6) the congruence of morphological and molecular phylogenies.

Douglas L. Theobald, “A formal test of the theory of universal common ancestry,” Nature, Vol. 465:219-222 (May 13, 2010).

Dr. Theobald might have had a point, were it not for the fact that:

• (1) Phylogeny and biogeography don’t always agree.
• (2) Phylogeny and paleontology don’t always agree.
• (3) Transitional fossils are often missing (or the “predicted” transitional fossils fall apart on closer inspection).
• (4) Hierarchical classifications often fail.
• (5) “Homologous” structures often have different developmental pathways or different structures often have “homologous” developmental pathways.
• (6) Morphological and molecular phylogenies are often incongruent.