That was extremely interesting and very educational.

Thanx for sharing.

Great video

Wow - this is a great find. I found this really informative. There's definitely some valuable info here.

I ended up more confused than enlightened.

Although he dismisses it out of hand, Dorian is as much a key as major (Ionian mode) and minor (Aeolian mode).

What's odd is that he treats Ab and G# as different keys. Notation doesn't change the sound of the note. But if you're including enharmonic equivalents, why arbitrarily stop at single flats? Bbb a valid key as well under that definition, which means there are an infinite number of keys.

I'd suggest that if you argued that modes aren't keys, there are only 12 keys - "key" refers to the "key note" of a scale, and there are only 12 distinct notes on my piano (when it's in tune).

I've wondered sometimes why they make us remember
which notes are sharped or flatted, when all they had to do was make a little mark on the appropriate notes. I mean, they dot notes, don't they? If it is a key with only two naturals, mark the naturals. All we'd have to do is learn to recognize
eight more notes.

Your point has merit, but accidentals are intended to serve a different purpose: inform the musician when a note is outside the given key.

So instead of cluttering up the music with something the musician knows - for example, all the Bs in a tune will be flattened - that information is given up front.

That way, the accidental flags when a note will be different than what was expected.

Oh, yeah, dcuny, you're right about that. It would wind up
causing more clutter than usefulness. Many of us, today,
play C, D, E, F, G and A majors, anyway. I have found,
playing guitar and a limited genre, that is PD Hymns,
that when the key is sharp or flat, the "muscle memory,"
if there is such a thing, pretty much sends the fingers
to the right strings without too much mental effort.