Obviously we have various terms to communicate specific shared states of mind:
Déjà vu - the illusion of having previously experienced something actually being encountered for the first time...
Cognitive Dissonance - anxiety that results from simultaneously holding contradictory or otherwise incompatible attitudes...
“On the Tip of one's Tongue” - Fig. [of a thought or idea] about to be said or almost remembered....
Likewise, I'm talking about a very specific cognitive state, that I'm sure most everyone has experienced, where you are unable to link or hold together multiple conceptions in order to achieve a final result.
You're able to think through the first few steps, but the whole thing breaks down and becomes incoherent. You can't quite reach that final outcome or solution, but it's right there almost within reach.
Then of course you run through it again, step by step, trying to 'take another run at it' – or perhaps another way to think about the problem - - but again, you just can't quite make that final iterative step to nail the solution.
I'm looking for something other than “dumb”, or “simple minded”, or anything too general or unduly pejorative – a term that can apply to anyone in such a situation, but it's pretty rare – and memorable - like Deja vu – or “tip of one's tongue”, but it's nothing to do with memory – it's specific to the building of something in your mind based on component conceptions.
A specific example I remember from years ago (but by no means limited to this) is the “Prisoners and Hats Puzzle” whereby to figure it out in your head you basically have to step through and hold present all the scenarios. (I forget what version of the puzzle I was first given.)
I recently came across another example regarding multivariate scenarios of baseball plays.