Short YouTube video by Lauren Bateman arguing that beginners do not need music theory to start playing guitar; she shares personal anecdote of writing and performing an album without knowing keys, and adds that theory becomes useful later for deeper understanding of chords and keys.
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Music purists are going to hate me because. No, you do not need music theory to learn how to play the guitar. I played the guitar for years without knowing any music theory or knowing what keys my own songs were in. I had written a whole album of music and been performing, and I didn't even know what a key was in music. Now does music theory down the road become more important? Yes. And I have educated myself in music theory because it is important to understand why things are the way they are in music. Why is it an A chord? Why is it a C chord? That stuff becomes important down the road. But in the beginning, when you're just getting started with guitar, don't worry about the music theory yet. Just get started, have fun. The music theory will come later.