Seriation sequence dating
Absolute dating techniques were not available to him (radiocarbon dating wasn't invented until the 1940s); and since they were separately excavated graves, stratigraphy was no use either.Petrie knew that styles of pottery seemed to come and go over time--in his case, he noted that some ceramic urns from the graves had handles and others had just stylized ridges in the same location on similarly shaped urns.The seriation method works because object styles change over time; they always have and always will.A good example of a change in artifact type is the development of hand-held PDAs from those first enormous cell phones. As an example of how change through time works, consider the different music recording methods that were used in the 20th century.Eyes are critical because, for the ‘vast majority of animals’, vision is their ‘most important link to the world’.
Dazu zählen Bier- und Weinkrüge, Wasserbehälter, aber auch die vielfach im Haushalt benutzten Brotbackformen, Feuerbecken, Lampen und Ständer, auf die man rundbodige Gefäße abstellen konnte. Der Nilton ist ein Verwitterungsprodukt, das der Nil aus den äthiopischen Bergen nach Ägypten transportierte.
Many kinds of eyes exist, but no progression of eye designs from simple to complex can be produced in the natural or fossil world.
Furthermore, the simplest ‘eye’, the eyespot, is not an eye but pigmented cells used for phototaxis; yet even it requires an enormously complex mechanism in order to function as a vision system.
In other words, artifacts found in the upper layers of a site will have been deposited more recently than those found in the lower layers.
Cross-dating of sites, comparing geologic strata at one site with another location and extrapolating the relative ages in that manner, is still an important dating strategy used today, primarily when sites are far too old for absolute dates to have much meaning.
The concept of irreducible complexity (IC) has become an important tool in intelligent design theory.