Where does original thought come from:

Is it an unoriginal thaught that has mutated ?
Is it a de novo idea that has landed out of the blue?
Is it a mixture / amalgam of two or more pre existing thoughts?
Is it as simple as leaving out a bit of an old thought?
or as simple as seeing something old in a new context / light ?

I'm sure all of tis can be applied to music !

Food for thought!!