Open Discussion: what are justifications, and why are they needed?

This meeting will be a live discussion of the title topic. This sort of discussion can't be settled in any particular way, but remains relevant for beginners and initiates to philosophy.

Here are some questions and comments that may help guide the conversation (feel free to bring questions of your own, as well):

A justification may also be called a ground, reason, principle, basis, cause, etc.

How does a justification work? How must it be related to whatever it justifies? Is there a structural relation between anything (in the broadest sense) and its justification such that they always accompany each other, or are they naturally indifferent and only connected by our judgment? If our judgment must connect them, then why would the justification really relate to what it justifies?

Does a justification have to be something real, or can it be ideal? For example, can something be two by virtue of twoness (Plato)?

Are justifications for something really needed all the time, or only in certain circumstances? For example, must there really be a justification for why things happen in nature?

"Τό γάρ αυτο νοειν έστιν τε καί ειναι." - Parmenides