### Does the Bible Really Say Pi = 3

I spend much more time on this site debunking religious arguments than atheist arguments, but I've just been reminded of one of the stupider arguments that some atheists use, so I thought I'd deal with it. Obviously, if you've read the rest of this blog, you know I'm an atheist myself, but I think that stupid arguments are bad no matter who's making them.

In 1 Kings 7:23, discussing Solomon's Temple, the Bible describes some of the furnishings thusly:

He made the Sea of cast metal, circular in shape, measuring ten cubits from rim to rim and five cubits high. It took a line of thirty cubits to measure around it.

Now, as everyone should remember from elementary school, circumference and diameter are related by the formula:

Circumference = Pi * Diameter

Or, to rearrange that equation a bit to solve for Pi:

Pi = Circumference / Diameter

Using the passage, we could then calculate Pi as follows:

Pi = 30 / 10or

Pi = 3

Again, thinking back to elementary school days, everybody should at least know a 3 digit approximation of Pi as 3.14. And so the argument goes, since the Bible gives such an erroneous value for Pi, it obviously can't be the inspired word of God. Here's one example of someone trying to use this argument, but I've seen it many other places.

In short, I think this is a rather stupid argument.

Pi is an irrational number. In other words, it doesn't matter how many decimal places you want to carry it out to, you'll only ever be able to write it as an approximation, and never an exact value. If you're still not following what that means, if you say that Pi is approximately 3.14, I could say - true, but it's really a bit closer to 3.142. But if you use 3.142, then I could say it's actually a bit closer to 3.1416. But if you use 3.1416, I could counter with 3.14159, and on and on forever. There's just no way to write pi as an exact value*. What this also means, is that even if you know the diameter exactly, you won't be able to write the circumference exactly, and vice versa.

So, when a scribe was describing Solomon's Temple, and wanted to give measurements of furnishings, there's no possible way he could have given exact values for the circumference *and* diameter of circular objects. It wasn't a limitation because the ancients didn't know enough. Even today, we couldn't do it. It's just a physical impossibility. So, the scribe rounded off his numbers.

Some people might still want to argue that the Bible would at least have been more accurate if it had used 31 cubits for the circumference of a 10 cubit diameter circle. I say - who cares? It's necessarily an approximation, so the scribe only used a single significant figure. Besides, there are plenty of sillier passages from the Bible, such as Genesis 30:37-43 or Judges 1:19, that skeptics can use in these types of arguments.

*This reminds me of the nerd obsession with knowing as many digits of Pi as possible. While this is certainly interesting for a variety of reasons, it's not really terribly practical. For example, if you use an approximation of Pi out to 10 decimal places (3.141 592 653 6), for a sphere the size of the Earth (diameter = 7917.5 miles), your calculation of the circumference would be off by less than 0.006 inches. And that's assuming you knew the diameter exactly. In reality, the uncertainty in your measurement would swamp the discrepancy from using your approximation of Pi.