Chengyu usage loop
理所当然
as it should be; taken for granted. Learn the modern situation first; the old story is useful only after the idiom has a job.
as it should be; taken for granted
Situation first
as it should be; taken for grantedA chengyu is a compressed judgment about a situation. Random idiom sprinkling is how learners sound like a proverb calendar.
Reading supports
Use these after the first listen. Pinyin is scaffolding; English is context; neither should become a sofa.
Literal meaning
as it should be; taken for granted
Story
This page focuses on the modern use of 理所当然, not just the old story.
Modern usage
Use 理所当然 in study contexts when the situation matches the meaning: as it should be; taken for granted.