Scales and why take off the 4th and 7th

[Steve S]

So I have grown super super frustrated with my guitar playing and how awful I sound so I went back to the basics and really dug into some scales. Which by the way on a weird way has been fun. So I have learned the MAJOR guitar scales, the Major TRIAD Arpeggios scales. Now I am working on the MAJOR PENTATONIC Scales. So the question is the MAJOR PENTATONIC is less the 4th and 7th notes. What is the reason for that. And maybe there is no reason for it just a different sound. So probably a stupid question and I am over analyzing it but just curious. I appreciate any responses. Thank you all for inspiring me. Thanks, Steve

[Jean-Michel G]

Hi,
The reason is that the 4th and 7th scale degrees are the only degrees of the major scale that are only a half tone above the lower scale degree. That makes them very active degrees, and also touchy from a harmonic perspective. Eliminating them eliminates most of the potential frictions.

Once you have ditched those degrees from the major scale, the relative minor scale obviously also lacks them.

Hope this helps.
JM

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