Shared and personal knowledge - one continuum?

 The class and my colleague/co-teacher and I explored that key TOK continuum - namely, the shared vs. personal knowledge dichotomy. I say dichotomy rather than binary, for this key TOK concept-relationship is centered around a dialogic set-up, i.e., one feeds into the other, and vice versa. And as it usually comes across with dichotomies, they tend to inspire more questions than help provide definitive answers. My current questions about the special relationship between personal knowledge (autonomous responsibility of the knower) and shared knowledge (vested and vetted interest of a community, in a given moment in time) include, but are not limited to:

• Could personal knowledge have an expiration date that is not in any way related to the effect that shared knowledge may expose it to? For example, could there be an autonomous expiration date? If that is possible, can personal knowledge ever be a justified true belief? 
• Is shared knowledge needed for any real-life progress to be made? If shared knowledge is about vested compromise, how relevant is its role in keeping society on an upwards path? Can shared knowledge ever be democratic in its effect and impact?

Right? Lots of interlinked questions feeding into more follow-up questions. I'd like to close by running with the following example. In my not so short life, I'd been educated into accepting a Solar System with Pluto as its member; I did not question it, for I neither saw the reason behind a potential dissent, nor did the shared knowledge attached to this claim ever strike me as something that should be tested (vetted scientific process). Yet, within the last decade, a shift has taken Pluto out of the equation, by reducing it to a dwarf planet status. Now, though Pluto's role in our collective memory is changing, my personal knowledge about this particular event, and its subsequent ripple effects is no different from when I first learnt of its existence (the planet, and not its role). Thus, my personal knowledge is in no way affected, though my understanding of the shared knowledge regarding this event is certainly one that accepts the change. Weird, right? Perhaps just in flux, as all dichotomies and the tales they help tell. 

Enjoy a bit of Pluto's colors