Print this pageAbstract: Evolution and Uniformitarianism
Organic evolution is compatible with methodologic uniformitarianism or belief in the constancy of natural laws, but, by definition, it is incompatible with substantive uniformitarianism, or belief in the constancy of physicochemical properties and rates of processes.
The phrase, "the present is the key to the past," is an incomplete description of the application of methodologic uniformitarianism and should be abandoned. Whether the present is defined as the interval represented by a human lifetime or by all of modern geology, it is too brief to permit direct observation of many important geologic phenomena. Many facets of evolution can be studied only by the use of geologic data. Some features of evolution cannot be investigated today because they span long intervals of time. Others operate so rarely that they never have been observed. For example, neither rates of extinction nor rates of speciation can be studied in the present world. Of special significance, the fossil record reveals that phyletic evolution customarily is very slow. This implie that most evolution occurs in spurts, by way of speciation, yet no one has ever witnessed a speciation event.
AAPG Search and Discovery Article #90961©1978 AAPG Annual Convention and Exhibition, Oklahoma City, Oklahoma