This assumption is based on a limit and on a rediscovery. The limit is the concept of growing up, which implies acceptances of convention and tradition that innovators avoid. Indeed, the designation of “immaturity” is frequently applied to innovators of all ages who constantly question the rules. To be mature is to become habituated to life’s prevailing norms, values and habits. In many cases this is the definition of mental health as well as of progress in cognitive, social and other domain where scales anchor in “age-appropriate” behavior.
Some writers see this as a progression from toying with many possibilities to an acceptance of probabilities to an accommodation of certainty. Innovation cannot thrive with this context. Certainty precludes options.
The rediscovery part of the assumption moves from the conformance of progression to the enthusiasms of childhood. How many times do children ask “why” and remain unsatisfied by our answers. And consider ideas. Having one as a child does little for the ego. But building one…and then using it—there’s the fun. Childhood projects often begin with a preference, a whim, an impulse. Calculations come later as the route unfolds. Surprises abound while zigging and zagging. Correlations and causalities are in suspension. For adults, the itch is to try something new and build on what works.
“Act your age” in conventional thinking is a blessing. For innovation it is a curse. This is a realm in which childhood’s end is another beginning.