New structures would be useless until fully developed (Talk.Origins)
New structures or organs would not develop incrementally because they would not function until fully developed. For example, what use is half an eye?
- Morris, Henry M., 1974. Scientific Creationism, Green Forest, AR: Master Books, pg. 53.
(Talk.Origins quotes in blue)
1. The assumption made by the claim is false. Structures and organs function quite well when they are not fully developed. Six-year-olds may not have the strength and agility of adults, but their arms, legs, and so forth function well enough to do a great deal.
While six-year-olds do not have the strength and agility of adults their legs have all their functional parts, all they need is growth. The claim uses the word "new". Evolution says that new structures or organs develop incrementally, by means of beneficial mutations followed by selection. Anything new, whether lungs, photosynthesis, legs or eyes, must have developed gradually, mutation by mutation, each one being selected and transferred to the general population. The point is that many organs and structures are difficult to develop incrementally so that each step is useful for the organism. That usefulness is the point of "fully developed". A child's leg has all the bones, muscles, ligaments and blood vessels in place as well as whatever neural hard wiring is necessary in the brain. All of that would need to develop in a gradual manner per normal evolutionary doctrine. There really is a problem with organs that are not fully functional in the sense that they are not useful. Organs "in process of development" would have some structures, but other necessary structures would not yet have developed which would make the whole useful.
2. "Fully developed" is not even well defined. Human eyes do not have the acuity of hawks, the dark sight ability of owls, the color discrimination of some fish, or the bee's ability to see in ultraviolet (see CB921.1). With so much more potential possible for the human eye, how can one claim that our own eyes are fully developed?
In context, when Morris said “fully developed” he clearly meant developed to functionality. All of the examples given above are just different types of fully functional eyes.