“Learn as much by writing as by reading.”

Its been my experience that to write anything requires a certain amount of previous knowledge, research, reading and then that ah-ha moment. The writer ends up learning more than is written.

Well said Mike, Norwalk. Such has been my experience also with writing and composing music. It is that ah-ha moment that science seeks to understand. Music explains it as alien interaction, a guiding star. Numbers and codification also carry the same inclination of influence. 

Music is a good example.  While learning guitar and experimenting with various chord progressions, you'll 'discover' nearly every Beatles song there is. ;-)  One can't know the experience of singing in harmony with others without actually doing it.  Learn by doing.