Its a matter of progression, and topic and context, no? All of which depends on where a particular learner or set of learners are in their exploration of a topic.
In the broadest terms, I like to think of it as a progression over time (ranging from a very short time to decades) from recognising uncertainty to tolerating uncertainty to celebrating uncertainty.
But without some uncertainty there is no challenge, just repetition, and mature learners (including many - if not most children) are characterised by radical scepticism.
So ... the reverse question ... what roles does 'schooling' play in undermining children's unbounded inquisitiveness, and making the route (back) to radical scepticism so long and painful - and why, oh why?