Twitter didn't give me the discussion of this important issue that I wanted, so here we are.
Really, why do we have both? I mean, in a game like 4e, they can have different roles in all the important stuff (combat), but fictionally, I cannot place these two in distinct niches. Fighter, Thief, Wizard, Cleric: yes, distinct fictional archetypes. Fighter, Thief, Wizard, Paladin: yes, distinct fictional archetypes. But Cleric & Paladin: no, not distinct fictional archetypes. Thinking about the Paladin confuses me on what a Cleric's supposed to be about, and thinking about the Cleric confuses me on what a Paladin's supposed to be about.
I'm interested in historical reasons why these both exist, but also in actual-play help. Like, if I play Dungeon World or something: What's the Cleric supposed to be that the Paladin isn't? And vice-versa.