A field guide to the ways reasoning breaks
Crowds and prestige
Also called Argumentum ad antiquitatem
Holding that something is correct or best because it is long established.
We have always done onboarding this way, so it works.
Ask what the practice was originally solving and whether that problem still exists.
Latin argumentum ad antiquitatem, 'argument from age'. Longevity is treated as a credential: if a custom has survived this long, it must be doing something right — a shortcut that can be true and often is, which is exactly why it gets abused.
The clinic keeps booking appointments by phone because that is how patients have always done it, despite the missed-call queue out the door.
A municipality defends a decades-old traffic junction on the grounds that it has served the town for generations, while the accident reports accumulate.
A family business refuses invoices by email because the founder signed every bill by hand, and desks now buckle under paper.
A music curriculum still spends its year on the syllabus its teachers inherited, because it produced fine graduates fifty years ago.