Necessity is the mother of ____, they say.

noun

1. A short keyboard composition featuring two- or three-part counterpoint
2. The act or process of inventing
3. Productive imagination inventiveness
4. Discovery, finding

noun

1. The act or an instance of inventing or creating one's identity or conception of oneself

   "her self-invention as a pop star"

idiom

1. Used to say that new ways to do things are found or created when there is a strong and special need for them