"there are three principal means of acquiring observation of nature, reflection, and experimentation. observation collects facts; reflection combines them; experimentation verifies the result of that combination."

what does the word enlightenment mean in this context?

The time of illumination

Explanation:

The word enlightenment in this direct context means the time of illumination

the artist used rapid brushstrokes.

it seems to me that yes they solo on the chord changes.  coltrane for sure solos on the chord changes. instead of changing scales, they use a different method over the chord changes. this melody is very  unique but may often times even be considered simple, which is quite common in this modal  type. for example, there are changes from the key of minor to major in this piece, which makes it  unique in its own way.