Signs and Houses appear to operate independently in Classical Synastry
by Kyösti Tarvainen
According to Sakoian and Acker’s synastry book The Astrology of Human Relationships (1976), having a partner’s Sun placed in one’s first, fifth or seventh house is beneficial for a romantic relationship. A study (Tarvainen, 2011) of 20,895 married couples from the Gauquelins’ heredity data confirmed the statistical significance of their assertion. This research explores the theoretical question of whether it is mainly the astrological signs that mediate this synastry effect. For example, the sign on the cusp of the seventh house or the Descendant sign is considered a key indicator for compatibility. Consequently, we explored whether the surplus presence of an individual’s Sun in their partner’s seventh house is primarily due to the Sun sign matching the sign on their partner’s Descendant. While there was indeed a relatively large excess of cases where an individual’s Sun in the seventh house was in the same sign as their spouse’s Descendant sign, there was also an excess in the part of the seventh where the individual’s Sun sign differed from the spouse’s Descendant sign. Yet, there was no solar excess in the part of the sixth house where the sign of the Descendant and the partner’s Sun were the same. So, it appears that favourable synastry occurs throughout the seventh house irrespective of the signs. A similar effect with positive synastry across the entire house occurred with the fifth house. However, in the first house, the pattern was identical except that when an individual’s Sun lying in the spouse’s twelfth house was in the same sign as their spouse’s Ascendant sign, it also appeared to favour marital prospects. This, however, may be due to the conjunction of the Ascendant and Sun, which is considered a favourable aspect between charts. Overall, this study suggests that signs and houses are distinct astrological factors, indicating a weakness in the Whole Sign House system, where houses align with signs.