What does it mean for a scale to be "complete in terms of tonality"?

Question

The Wikipedia page for "Pentatonic scale" contains the following quote (here's a link).

Anhemitonic pentatonic scales can be constructed in many ways. The major pentatonic scale may be thought of as a gapped or incomplete major scale.[32] However, the pentatonic scale has a unique character and is complete in terms of tonality. One construction takes five consecutive pitches from the circle of fifths;[33] starting on C, these are C, G, D, A, and E. Transposing the pitches to fit into one octave rearranges the pitches into the major pentatonic scale: C, D, E, G, A.

What is meant by the assertion that "The major pentatonic scale ... is complete in terms of tonality."?

Answer 1

Tonality typically means that music progresses through the diatonic functions: the tonic, predominant, and dominant. Typically that involves the I, IV, and V7 chords, although there are other ways to construct a complete diatonic progression.

That said, it’s difficult to form a predominant chord without using the 4th scale degree, which is missing from the pentatonic scale. Thus, the editor may be using terminology imprecisely, a problem which is noted on the article’s talk page.

Answer 2

'Tonality' seems to have taken on a vague mantle. Generally it would be a feeling that a piece is in a particular key, with an easily defined centre or 'home note/chord. This is seen in major and minor works throughout the last couple of hundred years. Yes, some modulate - which opens a new can of worms - is that piece now not tonal, or has the tonal centre just changed - temporarily, or permanently. Sounds semantic. Modal works can thus be seen as tonal - having the same diatonic notes as a major key, but having a different tonal centre. As an aside, Dorian works well, without having that defining leading tone that folk seem to consider imperative.

On to major pent. There have been many tunes - some very well-known, that use only the five notes of the pentatonic. They can all be seen (heard!) to have a specific tonal centre, and can all be harmonised using diatonic notes. That opens another can - is a tune truly pentatonic if the accompanying harmonies contain notes 4 and 7 from the full diatonic scale? For another day! However, pent tunes are complete entities, and hold together with a recognisable key centre, so could be construed as tonal. As far as the buiding of the five notes from the circle of fifths is concerned, I think it's serendipity and accidental.

P.S. - downvoters, please explain why!

Answer 3

The writer is expressing an opinion that a pentatonic scale may be considered as a subset of a major scale, or as an entity in itself - you can write and harmonise a melody using ONLY the 5 notes.

If you feel 'tonality' must imply functional harmony in a tonic-dominant sense, you should question his use of the term. Or you can try to understand what he's getting at, even if definitions are being stretched a bit.

This is a Wikipedia article, not Holy Writ. (And even Holy Writ has been known to contradict itself at times :-)

Answer 4

It's not. In fact, no scale is. Tonality is brought though by the harmony of a price not the scale used. Even the major scale which is the typical scale use to write something tonal is not "complete in tonality". You can write something just using the major scale that is not tonal at all.

The author seems to equate that a scale that can be built of a circle of 5ths is complete in tonality , but any diatonic scale can be including the Locrian mode which almost never would lead itself to having anything tonal built from it.