It occurred to me this morning the impermanence of memory, knowledge, and perhaps insights and wisdom. There does seem to be a conditioned sense of permanence of these concepts and the functioning of them but each time I remember, it has a bit different flavor from the moment that the event occurred. I wonder if I'm missing something here?

Each time we recall an event, the retrieval of the information modify the encoding of that memory. That's why they develop therapy for PTSD using MDMA, so that someone can recall a stressful event and re-encode it with a relaxed mindset. Meditation as the same effect as so many images of our past come to our mind and we get the opportunity to re-encode that memory with less affect.

You can read more about this here:
http://www.human-memory.net/processes_recall.html

Thank you Simon .

I experienced some disillusionment when considering the implications of the potential impermanence of insight and wisdom. I do want to believe that insights gained are maintained and I have been considering the effects of fruition, tastes of the unconditioned, as having some permanent effect, but am beginning to wonder about this. It seems that Sutras imply that there are permanent effects to insights and wisdom of these unconditioned experiences (e.g. post stream entry, and the progressive paths, etc..)Once experienced, the experience is lasting, although ever evolving I suppose, not necessarily permanent.

if you really get(get the point and realize) the insight it never returns but if you don't you will rediscover it. Basically what important is becoming aware of things you weren't aware before. You don't need to define or even make it into language of brain, basically insight resolves itself.
Mind is automatic?!, you will give it a job, for example you will start nitpicking/concentrate on suffering then in the back it is seen/known how mind is computing/comparing things/past experiences really fast and finally something arises and now when you can put it also into practice right away(or later) its a big fish. There is also small ones what frees the mind, its then easier and easier to go for higher samadhi.
Eventually mind is so pure that you can let go and identify yourself with the permanent one. Samadhi is after this event permanent*. Frution is samadhi too.
*permanet- for example you start with the lowest samadhi and go for the higher ones there is no shift, its continious going "higher",- you have become samadhi.

As for the memory, when too long in samadhi, thoughts can be forgotten instantly. Self expression skills at low. Reading long text strong effort needed. Ability to do something rutine starts getting on nerves quickly.

PS. i write things down like i did it replying to your post keeps the pressure and motivation high, i progress quicker this way.

I think it might be helpful to be clear about what an "insight" is and what "wisdom" is.

I tend to think an "insight" is just a brief moment of clear seeing -- of seeing through the mind's net of deluded, emotionally biased conceptual proliferation. In this case, insights are nice but aren't quite the point. The point is to dismantle that net in a more permanent way so that one has clear seeing as an ongoing experience, so that the mind is no longer actively generating those delusions on a moment-to-moment basis.

Brief moments of insight (according to this definition) provide motivation but aren't the goal, so it's not too relevant whether their effects are temporary or permanent, as long as one stays motivated to keep practicing.

And what is "wisdom"? Wisdom I think is understanding how the mind and the world works. As long as one continues to observe what happens with comprehension, and one retains one's faculties, wisdom will remain, because the sources of the wisdom (the mind and the world) will still be around.

There's perhaps an exception to this, in that one's mind can change through the practice. So if one dismantles the process of dependent origination within one's own mind, that process won't be around anymore for one to observe, and one might forget how it used to work. I don't think there's a real problem with this though. Either one is liberated (no more dependent origination) or the process is still around to observe (so the source of wisdom is there).

Just a few thoughts (hoping they make sense),
C