How does one interpret interceptions?
I'm wondering if when there is an intercepted house do we ignore it and just count it as the house that is "supposed" to be the house. For instance if theres no number in the fourth house quadrant, but there's a planet there do we interpret it as being in the 4th house or are you supposed to interpret it differently? And for the houses that have two numbers do you interpret the planets as being in those two different houses at the same time?
If a planet is in the 4th sign from the ascendant sign, then it is in the 4th house regardless of if the 4th cusp or multiple cusps are there or not.
Cusps do not specifically indicate house placements.
This is of course for Vedic astrology, and Jaimani uses this house counting from signs (whole sign system). I think a rare few Western astrologers use cusp placements to determine the "size" of houses, but for me it really complicates things, and it simply doesn't work with the majority of Vedic astrology techniques/yogas. I like things simple; Whole sign system, rashi aspects, etc.
There should be some info somewhere in Ernst's stuff where he elucidates what the meaning of the cusps are. They are kind of like a manifested object/person/thing in the world that represents something from a house, like the 4th cusps being "mother" (I think). Or reading the cusp in the chart, this is what your mother might be like.
a planet is in a sign from the asc. and this helps see if that planet will manifest well or with more stress. If in 6/8/12 it will manifest with a lot more stress, in an angle or trine, it manifests most easily, in 2/3/11 it gives a bit of stress as well to manifest it. Thats all we do with house positions on a basic level. And that is all based on signs from the asc. We also do many yogas in this same way.
Then there is the matter of a planet impacting a house cusp. The planets are the produces, the house cusp is the concrete thing produced. For this the cusp has no impact on the planet. The planet impacts the cusp. If its inthe same sign as the cusp or aspect the cusps, the planet is impacting it.
That's all there is to it.
I would focus on the 2nd cusp. ALso, the second from mercury is very important for that.