Math and religion. Oh how long I’ve wanted a post that combines these two topics.
Anyway, some Bible skeptics like to criticize the Bible for claiming that pi is equal to 3 based on this reference:
(1 Ki 7:23 NIV) 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.
The circular object is 30 cubits in circumference and 10 cubits in diameter. Thus the Bible says pi = 3, LOL. Right?
Well, it’s not LOL, and it doesn’t take some of the odd gymnastics Biblical apologists use to see why.
It’s all about significant digits. The concept of significant digits helps us determine how precise a number is and how precise we can expect any calculations to be.
For a real-world example, let’s say you’re driving to Houston, desperate to visit me. You see one of those signs that says “Houston 100”, indicating the city is 100 kilometers away. (Yes, I know it’s miles and feet in the US. I want to use metric. Hrmph.)
Imagine you step out of your car and stand by the sign. Then you take a step 1 meter backwards away from Houston. You wouldn’t say “I’m 100.001 km away from Houston now!” Why?
The sign has a precision to the nearest km. We can’t tell whether the sign is actually 100.1 km, 99.729 km, or somewhere in between. There’s a limit to how precise we can be.
Let’s go back to the Bible passage. The dimensions are 30 cubits and 10 cubits, both numbers with only one significant digit. Without any further information on the measurements’ precision, calculations can only be expected to be precise to one significant digit.
30 / 10 = 3. Pi to one significant digit is 3. The Biblical figure for pi is as accurate as it can possibly be given the measurements. Nothing to see here. There are enough questions about the Bible not to dwell on a non-issue.