Do paladins have to choose a deity?

@JeremyECrawford Do paladins have to choose a deity? Is following a philosophy or ideal acceptable?

— Matthew Domville (@mattdomville) September 25, 2015

There's no rule that a paladin must serve a deity. But a DM might require it, depending on the world used. #DnD https://t.co/LRKyjCAS4y

— Jeremy Crawford (@JeremyECrawford) September 25, 2015