II. Impulses of Transformation for Man's Artistic Evolution I

You can now also see that the existence of the major third and the minor third really corresponds to the incorporation of the astral body in our whole human organisation. If you look up the relevant passage in my book Theosophy you will see that there is an overlapping of what we call the sentient soul on the other. Therefore what I described as an interval of a third can correspond either to the astral body or to the sentient soul: in the one case we have the major third and in the other the minor third.