C d e F G a b C 2min 3min 4Maj 5Maj 6min 7dim

What determines that the intervals 2,3,6 are minor and the intervals 4,5 are major? I would assume the same applies to the diminished.


Those are not intervals - they're triads made on each of the diatonic notes of the scale. Taking each as a root of a triad in its own right, the note but one after it is either making a major or a minor third. There is the interval. If that interval is major, so is the triad. Minor interval = minor triad.

The triad built on the 7th note contains two minor thirds - or a minor third and a diminished 5th. Thus it's called a diminished triad.

  • Got it. Thank you – daniel May 10 '19 at 19:06
  • I think OP might actually be referring to intervals, but is using the symbols generally reserved for chords. Thus CdeFGabC would be correct, as it's just the interval qualities in the case of the letters. – user45266 May 10 '19 at 19:06
  • That is correct. Was really struggling on how to phrase my question. – daniel May 10 '19 at 19:08
  • This is almost true. Every (diatonic) chord has at least three notes and the interval distance between each pair can be WW (major 3rd) or WH (minor 3rd).. So C E G is a Cmajor ... C to E is WW and E to G is WH. (Maj3 + Min3). So there's four combinations. M3+m3 = major chord m3+M3 = minor chord m3+m3 = diminished M3+M3 = augmented (Is a diminished chord a minor triad? It starts with an m3.) (Is an augmented chord a major triad? It starts with an M3.) – Randy Zeitman May 12 '19 at 0:39
  • @RandyZeitman - moot points! I've always considered augmented triads as major, but have mixed views on diminished as minor. They certainly aren't major! I once stated on this site that a major triad is made up from a M3 and a m3, but consensus is that it's M3 +P5... – Tim May 12 '19 at 7:02

These are "degrees" of the major scale. They are also intervals relative to the first note. But ALL of them are MAJOR. I think you are confusing the concept of major and minor with consonance and dissonance. The interval from Do to Re is a Maj second. The flat Re (C to Db for example) would be a minor second. And so on. Now, many other intervals exist in the major scale. For example the interval from Mi to Sol (3rd to 5th) is a minor 3rd. The interval from Fa to Ti is a diminished 5th.

I should say, correcting myself, that the 4th and 5th (Do - Fa), (Do - Sol) and the Octave are considered "perfect" intervals. We don't say major 5th, we say perfect 5th. There is a reason for this that has roots in the physics of sympathetic resonance and harmonics.

There is a formula in music theory for defining minor diminished and augmented intervals and this definition does depend in some way on whether intervals are perfect or not.

Consonance and dissonance refers to the quality of the interval being pleasant or "unpleasant" (tense). But these designations are quite old fashioned. Helmholtz did a physics based analysis of this using wave theory in the late 1800s trying to demonstrate a physical basis for these qualities.


As you talk about intervals, minor, major, diminished it is to assume that you know the names and terms of the eight intervals too, such as second, third, fourth, fifth etc.

Mind that the Arabic numbers are used referring to the chord tones: 135 (triad) 1357 (tetrad) etc.

Mind that the names of the intervals are used to sign the distances between to tones of a scale as-well for naming the degrees themselves.

To assign the degrees of a scale in music you have to use roman numbers.

your comment on Tim’s answer:

Was really struggling on how to phrase my question.

How to phrase your question:


(this is the scale of C, a “ladder” of 8 degrees, of which the 8th is named and sounding like the first again.)

We see that the intervals between the degrees are not all the same: there is 1 half step between ef and cb, all others are whole steps. The best representation is the keyboard where you can see that the steps EF and BC are closer together as there is no black key between these white keys.

enter image description here

what is here minor, major, diminished?

not all beginners know that major means actually big and larger and minor means small or smaller while diminished is probably known by math as even smaller, somewhat as reduced.

The terms minor and major are referring to the intervals as 2nd, 3rd, 6th and 7th.

If you consider these intervals there are two kind of 2nds:

EF -> half step (only one halftone between): minor 2nd C D -> whole step (2 halftones between): major 2nd

now there are (for our concern) 2 kind of 3rds built of half and whole steps: (h or w)

W W = major

W H = minor (or H W)

(the same assumptions can be made for all other Intervals mentioned above - counting half and whole steps...)

your question is concerning the 3rds or/and the triads built above the degrees:

2min 3min 4Maj 5Maj 6min 7dim

I ii iii IV V vi vii(dim)

uppercase = major

lowercase = minor

from here you can develop the answer to your question:

What determines that the intervals 2,3,6 are minor and the intervals 4,5 are major? I would assume the same applies to the diminished.

the thirds built above each degree are minor or major depending of the half steps a and whole steps they include.

The triads are major or minor depending of the 3rds built above the root tone:

major + minor third = major triad

minor + major third = minor triad

minor + minor third = diminished triad

(the latter is called diminished as the result of 2 minor thirds is a summary of a diminished 5th while all others triads are perfect fifths including 1 minor + 1 major 3rd or 1 minor + 1 major 3rd.

  • Wow! That answers my question(s) from any angle I can think of. Thank you. – daniel May 14 '19 at 4:54

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