Relative and numerical dating techniques
These skeptics do not provide scientific evidence for their views.
Current understanding of the history of life is probably close to the truth because it is based on repeated and careful testing and consideration of data.
In addition, like any good scientific measurement, every dated boundary has an uncertainty associated with it, expressed as " - X millions of years".
These can not be included in the diagram for practical reasons, but can be found in Harland , 1990, along with a detailed description of the history of earlier-proposed time scales and the terminology, methodology and data involved in constructing this geological time scale.
All these labors have not led to a single unexpected finding such as a human fossil from the time of the dinosaurs, or a Jurassic dinosaur in the same rocks as Silurian trilobites.Since then, geologists have made many tens of thousands of radiometric age determinations, and they have refined the earlier estimates.A key point is that it is no longer necessary simply to accept one chemical determination of a rock’s age.Paleontologists now apply sophisticated mathematical techniques to assess the relative quality of particular fossil successions, as well as the entire fossil record.These demonstrate that, of course, we do not know everything (and clearly never will), but we know enough.