Relative dating of geological features
Thus the main evidence for evolution is based on the assumption of evolution.
A significant development of recent years has been the fact that many evolutionary geologists are now also recognizing this problem.
If you doubt it, bring in a suite of good index fossils, and the specialist without asking where or in what order they were collected, will lay them out on the table in chronological order." That is, since evolution always proceeds in the same way all over the world at the same time, index fossils representing a given stage of evolution are assumed to constitute infallible indicators of the geologic age in which they are found.
This makes good sense and would obviously be the best way to determine relative geologic age — if, that is, we knew infallibly that evolution were true! There is such a vast time scale involved that no one can actually observe evolution taking place.
They no longer ignore it or pass it off with a sarcastic denial, but admit that it is a real problem which deserves a serious answer. which starts from a chronology of index fossils, and imposes them on the rocks.
The use of "index fossils" to determine the geologic age of a formation, for example, is discussed in an interesting way in an important recent paper by J. Each taxon represents a definite time unit and so provides an accurate, even 'infallible' date.
Ager, who is also Head of the Geology Department at Swansea University, notes the problem involved in trying to use minor differences in organisms (that is, what creationists would call horizontal changes, or variations) as time markers.
— If we read the record rather literally, it implies that organisms of new grades of complexity arose and radiated relatively rapidly."changes, however, are not really relevant to the measure of geologic time, since such changes occur too rapidly (e.g., the development of numerous varieties of dogs within human history) to be meaningful on the geologic time scale, and are reversible (e.g., the shift in the peppered-moth population of England from light-colored to dark-colored and back again).
Thus evolutionary changes in fossils are essential to real geologic dating, but they are impossible to prove. The dating of the rocks depends on the evolutionary sequence of the fossils, but the evolutionary interpretation of the fossils depends on the dating of the rocks.
"That a known fossil or recent species, or higher taxonomic group, however primitive it might appear, is an actual ancestor of some other species or group, is an assumption scientifically unjustifiable, for science never can simply assume that which it has the responsibility to demonstrate.
— It is the burden of each of us to demonstrate the reasonableness of any hypothesis we might care to erect about ancestral conditions, keeping in mind that we have no ancestor alive today, that in all probability such ancestors have been dead for many tens or millions of years, and that even in the fossil record they are not accessible to us." "Likewise, paleontologists do their best to make sense out of the fossil record and sketch in evolutionary sequences or unfossilized morphologies without realistic hope of obtaining specific verification within the foreseeable future." It would help if the fossil record would yield somewhere at least a few transitional sequences demonstrating the evolution of some kind of organism into some other more complex kind. "The abrupt appearance of higher taxa in the fossil record has been a perennial puzzle.
But biologists in turn have simply assumed evolution to be true. For most biologists the strongest reason for accepting the evolutionary hypothesis is their acceptance of some theory that entails it. The temporal ordering of biological events beyond the local section may critically involve paleontological correlation, which necessarily presupposed the non-repeatability of organic events in geologic history.