I would think we all play by ear, at least to some extent. But that’s stating the obvious, I guess. 😯
I know a little theory, and am learning more as I go. Surprsingly, it’s not as hard as I thought. Don’t get me wrong, it still makes me want to douce my eyes with gasoline sometimes (but that’d cost too much!), but as I slowly wade through the murky water, parts of the bottom become visible, if you catch my drift. Hehe. Sorry, that was cheesy.
But learning your modes is a good place to start, anyways. It’s helped me understand how and why some songs are the way they are, and certainly has helped me understand chord formations better, as well as why certain chords & certain structures work together.
A good song doesn’t sound good by mistake – it sounds good because it fits in a certain type of mathmatical formula, and we as humans recognize this audible formula, whether we know how to explain it or not. You don’t need theory to know a good song – that type of ability is built inside all of us. Music is a very primal instinct we all have; unfortunately it’s not stressed as much as it should be (or at least it’s not conveyed as well as it could be) when we are younger.
Take the major scale, for example. This is where these 7 “starter” modes (or whatever you call them) are derived from. Everybody I’ve ever met, musically inclinded or not, can hum “doe rae me fa so la tee doe” – VIOLA! The Major Scale. Once you can break that down into Ionian, Dorian, Phrygian, Lydian, Mixolydian, Aeolian, and Locrian, the music simplifies itself tenfold.
Sorry for the sort of “off topic” rant….time for me to go to bed!