Genius can be defined simply as high intelligence/ ability plus creativity - but what is creativity?
Although there is a scientific literature on creativity, describing its psychological mechanism and purporting to measure it quantitatively, there is a serious problem when science addresses creativity - a category error; in the sense that insofar as creativity is captured by science then science captures is precisely not creativity.
What real creativity is, is something uncanny.
It can perhaps best be understood as a consequence of the bringing to bear nothing less that the whole personality upon a problem; not just for a Eureka-moment of illumination, but also for the preceding 'Genius Quest' which may last for years.
Creativity has a source beyond science - inspiration is both within and without; it both seems to come from inside by in-trospection; and from outside by being in-spired like breathing-in.
Creativity is thus an inner fire, and also a yielding to destiny - both are unique. Our inner fire is distinctive, and our destiny is also distinctive - therefore creativity is a key to working-out our uniqueness.
The variations in real creativity between people are therefore in essence a matter of value - value to the creative person; so behind public perceptions and fashion, differences in underlying creativity correspond to a difference between those who are more- and less- spiritually advanced in terms of discovering, realizing and developing themselves - in the way, in the direction, along the path that is their unique destiny and necessity.