And the Gileadites took the passages of Jordan before the Ephraimites: and it was so, that when those Ephraimites which were escaped said, Let me go over; that the men of Gilead said unto him, Art thou an Ephraimite? If he said, Nay; Then said they unto him, Say now Shibboleth: and he said Sibboleth: for he could not frame to pronounce it right. Then they took him, and slew him at the passages of Jordan
— Judges 12:5–6
A Shibboleth acts as a shared, community-wide password that separates out the In Group & Out Group. The mere fact you have the capability to answer correctly is enough to validate you.
memes act as shibboleths. If you laugh at me saying “And They Were Roommates” or “Uh, yeah, I sure hope it does”, I know we have some shared cultural context and how to get along with you along those lines. If you know, you know.
Shibboleths are time and context based, and can expire.
If you say “When does the narwhal bacon? At midnight.” you authenticate yourself as someone who was a reddit user in 2011, but not necessarily one who uses it today. Or, since it’s now common knowledge, someone who’s just heard of it through Cultural Osmosis. Ironically, the word Shibboleth itself is no longer an effective shibboleth.
See Also
- Nature Shibboleths validate based on ability, rather than knowledge.