Why is it that a progression 6\4 to 5\3 needs special
attention such that the 5\3 can not simply be left blank
as normal {and is sometimes figured as just 5}.
Thanks

Well, when I studied theory (and also used figured bass) we would write 6\4 5\3 but place a bracket under that progression identifying that movement it as representing V.

It gets special attention (in a cadence setting) since a second inversion chord is not representative of its 'parent' triad, so to speak. There are other ways to state this but I'm guessing they won't be all that different. We all studied different theorists and everyone thinks their way of looking at something is the best way.

Thanks Dave.

I don't understand when you say ".......
..identifying that movement it as representing V."
Typo?

In your learning, why was the 6\4 not really
representative of its 5\3 parent ?

Thanks

If you substitute progression or harmonic progression for movement, would that be clearer for you?

At a cadence (in traditional theory) I was taught that a 6\4 harmony was not really representative of its parent triad and the two chords were grouped together to represent V. There are different ways of looking at this and you do what you have to do to pass a theory test.

The problem with how harmony theory is commonly taught, is that there is no link to actual music and sound. The rules reflect music in the same way that grammar reflects speech. We get a feel for nouns and verbs first by speaking, and then we get the grammar - but in the way music theory is taught, it's the opposite. I first tried to break away from this after passing my last level of rudiments, by going over the whole book again and exploring it all on the piano and more.

6/4 is second inversion, and the first place we learn it is in I64 V (or V7) I - say in C major - C/G to G(7) to C (final cadence). When in C major you have G in the bass, your ear hears that "G-ness" strongly as part of the bass line. It suggests C and G simultaneously, but since the harmony is C, you still hear it as C - but there is a small ambiguity. Meanwhile as your ear follows the bass line, (notes) G G C. The I64 acts like a kind of bridge, stressing that we're going to the Dominant, and already having that "G-feeling" but still the I chord, then becomes the real Dominant, and then we have a sudden plunge down a P4 from G to C or a swoop up a P5 from G to C.

One of my theory books - Horwood - presented something like 8 ways of using a 64 chord, cautioning to be careful not to just use it anywhere - it seemed insane. And then I wrote an exercise where I did just put the 64 somewhere for no reason and a friend looking at it said that it sounded odd because it was ambiguous. Meanwhile over in the beginner theory thread I wrote a minor version of Happy Birthday, and it first contained G#dim to Am/E which broke two theory rules ---- invert the viio, and have a good reason to use 2nd inversion. viio-Im suggests a weak cadence, but the 64 (Am/E) suggests that the Am is about to move to E... and then it doesn't. And if it is about to move somewhere, what is it doing at the end of a cadence, which suggests completion?

... One more thing, what's great about figure bass, you don't have to concern yourself with analysis per se, it's just the intervals above the bass.

Grouping the (cadential) 6\4 ... 5\3 under the umbrella of V is just simple functional analysis ... and others will view this differently I'm sure.

This must be the insane thing in one of my theory books where in the key of C major, C/G to G7 to C was shown as V64 to V7 to I, when C/G clearly is NOT a 2nd inversion G chord. They drew a line under like this V64 V (not a hyperlink ) to show it as one unit. I understood the logic, which is that you "hear it" as being "part of the Dominant thingy", but essentially it seemed misnamed and confusing. I'd write it that way for an exam, but write it as I64 for myself the rest of the time.

It's notated that way to show the voice leading. The notes represented by the 6/4 lead directly to the 5/3.

It's just a pedagogical tool theory teachers use to make sure students understand how the 6/4 harmony is handled.