There is a plasticity of learning at the crest of development, which itself rests upon older striations which have calcified into their respective strata. The former depends upon the latter and vice versa: to effectively learn, one has to stand upon the stable and held-fast and dependable with confidence. Too much flexibility of trial and error and too many possibilities means the dispersal of one's efforts and a loss of movement and purpose. One has to be confident of what works and what is true, to measure further attempts against those things.
But on the other side of that coin, it helps to have some flexibility in what has been developed as well. As greater conditions change, what works and what is true could change, and if one is measuring all of one's efforts of trial and error against an increasingly falsifying body that refuses to change, one is also in trouble, and dispersing one's energy and movement in a different way.
