The Greatest Show on Earth, Chapter 4

Chapter-by-chapter thoughts on Richard Dawkins’ The Greatest Show on Earth: The Evidence for Evolution

by John C. Snider © 2009

Chapter 4: Silence and slow time

Oooh, the colors!  The Greatest Show on Earth boasts four sections of full-color illustrations, which is very cool (and probably explains the book’s $30 cover price).  Anyway, the first section of illustrations is bound into the middle of Chapter 4.

How do we know the earth is 4.6 billion years old?  Creationists, of course, claim it’s as little as 6,000 years old, and they have all sorts of clever-sounding-but-not-so-clever-actually arguments.  One of their most common plaints is that carbon-14 dating is rife with inaccuracy.  Dawkins reminds us, however, that carbon-14 (which has a  half-life of about 5,700 years) is useful primarily in determining the age of things that are less than, say, 60,000 years old.  In other words, carbon-14 is not used to determine the age of 10o-million-year-old dinosaur fossils.

But of course, any dating system using so-called radioactive clocks (which rely on our knowing the half-lives of various elements), has some inherent measurement error, and is subject to some guesswork.  Nonetheless, Dawkins points out that scientists rely on a number of different dating systems, from which we can triangulate (or quadragulate or quintagulate?) a pretty accurate estimate of 4.6 billion years.  The fact that the various dating systems converge on that number is a pretty good indication that the scientists know what they are doing.

What I find totally kick-ass is that we don’t have to rely on fancy-schmacy radiochemistry to know that the earth is well over 6,000 years old.  Dawkins gives a summary of the technique of “dendrochronology” (i.e. dating objects based on a well-established timeline found in, of all things, tree rings).  Trees form rings on an annual basis, and the thickness of each ring is an indication of the overall weather conditions for that year; e.g. a warm, rainy year will yield thicker rings, and vice versa for a dry year.  Historians are able to establish characteristic tree ring “fingerprints” based on historical weather records, and thus are able to, as Dawkins puts it, “daisychain” their way back through time, lining up ring patterns for trees that grew in overlapping time periods, extrapolating back to a time well before human beings kept written meteorological accounts.  In this way, one can theoretically establish an unbroken tree ring record stretching back many thousands of years–which scientists have done, going back to 11,500 years.  So much for the 6,000 year old earth!

Finally, Dawkins decimates the plausible sounding, but ultimately ridiculous Creationist explanation for the stratification of the fossil record.  I’ll let you read that for yourselves, but I think anyone in a live debate with a Young Earther will be well-equipped to destroy the “Noah’s Flood” argument once you’ve read this chapter.

Oh, and remember back in Chapter 1 Dawkins insists his audience includes the so-called “history-deniers”?  (A specious argument, I believe, since it’s hard to imagine reaching out to a selected demographic by insulting them.)  Dawkins convinces me he isn’t serious about reaching these people, since he opens Chapter 4 by calling Creationists “worse than ignorant” and “deluded to the point of perversity.”  Make no mistake, I do think they’re ignorant and deluded, but if I were trying to reach out to them I wouldn’t say it to their faces!

On to Chapter 5…!

The Greatest Show on Earth is available at Amazon.com and Amazon.co.uk.

Read my thoughts on Chapter 3.

Read my thoughts on Chapter 2.

Read my thoughts on Chapter 1.