I ask again, is convergence antithetical to common decent? If you answer no, how do you explain this in light of Campbell’s statement above? Would you at least agree it disrupts evolutionist efforts to construct phylogenies?
Anthithetical: no.
Campbell's statement was stating unreliability of using similar morphology as the ONLY criteria for phylogenies. One must also consider geographic isolation and fossil intermediates from separate common ancestors. The use of genetic similarity and markers are also very useful in determining if convergent evolution occurred.
For instance, if you ask four friends to meet you at the town square and each friend lives on opposite sides of town, would you assume they took the same route to reach the town square? Convergent evolution describes different phylogenies that are originially morphologically different but become similar due to similar niche pressures. If design were an element, analogous functions would have analagous genetics. But in fact the opposite is true. Solutions to a problem give rise to similar function but genetically different pathways along lines that support a common ancestor.