I usually solve issues like this by writing the thing down, carefully showing my work, and filing the resulting notes in a central, trusted place with good indexes and lots of links to sources and related ideas where available. If I go back later and have to try to understand my notes or find that my mind has changed, I figure out what I was going on about and why, then make copious annotations. This way, I export large portions of my mind to the environment. If I need to demonstrate to myself or somebody else that, for example, I can prove X, I can just pull the relevant notes and work them as needed into some sort of document.
I usually solve issues like this by writing the thing down, carefully showing my work, and filing the resulting notes in a central, trusted place with good indexes and lots of links to sources and related ideas where available. If I go back later and have to try to understand my notes or find that my mind has changed, I figure out what I was going on about and why, then make copious annotations. This way, I export large portions of my mind to the environment. If I need to demonstrate to myself or somebody else that, for example, I can prove X, I can just pull the relevant notes and work them as needed into some sort of document.