Whether they're handed down by God or Jim Bob, rules are what make the Duggar family tick.
Even if you're a casual fan, you're probably familiar with the Duggar courtship rules, the dress code, and the bizarrely regimented lifestyle that governs life on the compound.
Some of these rules are expressed openly.
For example, many episodes of Counting On have featured various members of the massive Duggar clan explaining the many things they're not allowed to do prior to marriage.
(The list of what's not permitted is much, much longer than the list of what's allowed.)
But there are other rules that are shrouded in mystery.
Take, for example, the Duggar policy regarding social media accounts.
It's long been rumored that Duggars who are not either married, engaged or courting are not allowed to post on social media.
It was widely assumed that it was for that reason that the still-single Jana Duggar doesn't have a social media account.
This became a matter of public discussion when Jessa Duggar posted the above photo of her sister earlier this week.
"I think their family has their own rule that they can’t have their own social media until they are in a relationship," one fan commented.
Jessa was having none of that talk, and she was quick to cement her place as the most outspoken Duggar daughter by immediately clearing the air:
"It’s not a rule, it’s just coincidence," Jessa responded, adding a laughing emoji to make it clear she's not taking the situation too seriously.
Of course, that emoji also served to confuse the issue a bit.
Is Jessa really saying that it's just a coincidence that Michelle and Jim Bob's kids start social media accounts only after they've announced their courtships?
Is she actually suggesting it's a pure coincidence that Jana is the only adult Duggar without any social media presence, and she also happens to be the only one who's single?
We have a hard time with that one, but we doubt the Duggars really care.
It's always been sort of understood that part of what the family offers is wholesome fiction, and fans seem okay with that arrangement.