Problem-Solution Cycle and Expertise over Time

Where,
P represents Problem
S represents Solution to Problem P
E represents Expertise
t represents Time

Over time, solution to existing problem creates additional problems which, in turn, require new solutions.

A certain level of expertise (skills/knowledge/mindset/worldview) allows one to come up with a solution to the problem presented.

Once in a while, a problem presented would not be solvable at the existing level of expertise and thus additional expertise (skills/knowledge/mindset/worldview) is required to create a solution to the problem presented.