VLD: "The English Common Law has been around for quite some time, at least since the 12th Century or so,...."
English Common Law draws heavily on Roman Law, particularly the Code of Justinian (529 AD) which brought together laws dating back to the founding of the Roman Republic, including the Twelve Tables (c 450 BC).
Westerners had a legal system system before anyone outside of Israel even heard of Moses. Taking the entire code of Justinian and the entire code of Moses, more of our modern law is derived from Justinian and the Romans than from Moses and the Hebrews.
So when Farmer talks about the code that has sustained Western Civilization for 2000 years, he must be referring to the Code of Justinian and its forebears.