So I was thinking, similar to sharp and flat notes, interval usage is contextual. In the same way that Bb is the same as A#, a diminished fifth is the same as an augmented fourth, etc. I understand when you would use flats or sharps, but I am a little more confused on intervallic values.
I understand how they would work in a scale: if the note is the fifth degree of the scale and a tritone above the root, then you would clearly refer to it as a diminished fifth rather than an augmented forth; but what happens when there is no scale to base the intervals upon? Does it even matter?