## Monday, October 10, 2016

### Jerry Coyne cannot be expressed as A/B

Jerry Coyne has a post of the irrationality of pi. Fair enough, that's a rather cool subject. But, being Jerry, he can't resist a gratuitous comment-- one that he thinks is humorous when in fact it's just tired and old. Yes, it's everybody's favorite classic: Jerry is once again asserting that the bible implies that pi = three.

Except it doesn't. Yet hardly a week goes by where I don't read this classic used by an atheist (color him smug) as an irrefutable "gotcha."

Jerry is referring to:

And he made a molten sea, ten cubits from the one brim to the other: it was round all about, and his height was five cubits: and a line of thirty cubits did compass it round about. (1 Kings 7:23)

Aha! A circumference of thirty and a diameter of ten means pi =30/10 = 3. Either Solomon’s Temple was built in Indiana or we have a serious problem.

I'll say it differently this time.

In grade school I was taught that the diameter of the earth was eight thousand miles. And I was taught that the circumference of the earth was 24 thousand miles. At no time, either in grade school or later, did that imply that I had been taught that pi was 3. My public school teachers were not secretly fundamentalist baptists intent on teaching us Jesus Math. No, they expected us, even an an early stage, to understand round numbers and appropriate simplifying imprecision when precision is just pedantic.

I bet if you ask Jerry for values of the diameter and circumference of the earth there is a good chance he'll give the 8K and 24K values. And if you point out those answers imply pi = 3, he'll complain that he was just giving approximate numbers and the the earth isn't perfectly round anyway. But he won't allow the same imprecision for the biblical writers, who were not dictating a CAD blueprint.

I know what my elementary school math teacher would say to Jerry: C'mon, don't be stupid.