Argument from poor design

The argument is structured as a basic modus ponens: if "creation" contains many defects, then design appears an implausible theory for the origin of earthly existence.

This predicts that features that were evolved for certain uses are then reused or co-opted for different uses, or abandoned altogether; and that suboptimal state is due to the inability of the hereditary mechanism to eliminate the particular vestiges of the evolutionary process.

[30] While the appendix has been previously credited with very little function, research has shown that it serves an important role in the fetus and young adults.

Endocrine cells appear in the appendix of the human fetus at around the 11th week of development, which produce various biogenic amines and peptide hormones, compounds that assist with various biological control (homeostatic) mechanisms.

In Gould's words, "If God had designed a beautiful machine to reflect his wisdom and power, surely he would not have used a collection of parts generally fashioned for other purposes.

Orchids are not made by an ideal engineer; they are jury-rigged...."[36] The apparently suboptimal design of organisms has also been used by proponents of theistic evolution to argue in favour of a creator deity who uses natural selection as a mechanism of his creation.