Do you really need music theory? (FAQ) 

As a guy with three different degrees in music, my take is that knowing music theory is very helpful, particularly if you want to understand the construction of a song. But I would submit that it's definitely not a requirement, either for enjoying music or for creating it. In fact, sometimes I subscribe to the "analysis = paralysis" point of view. There are times where thinking too much about the music is counter-productive. Just play it.

Knowing music theory is Great, but some players that know alot of theory think to much when they play. Music to me anyway is more about sound and feeling. You need technical ability also to be able to play what you hear in your mind for example so that is also extremely important. I look at music theory as being book smart. While actual playing time and experience as being street smart in the world. So if you have both you are even more well versed, but I don't think music theory is really needed for everyone. Look at George Lynch for example. He openly admits to not knowing alot of music theory, but when you listen to his playing he clearly knows EXACTLY what works and how to compose a song and his guitar works is as good as any guitarist from the 80's and 90's then comapre George to Randy Rhoads and Randy knew all kinds of music theory. Point being both guys are incredible players one knew theory inside and out and one didn't but both are incredible guitarist.