Mesembolesis

mes-em-BOH-leh-sis

greek: μεσεμβόλησις (Mesembolēsis)

Definition

Mesembolesis (Greek mesembolēsis, "intervention, interposition") is a Hellenistic aspect term, usually rendered "intervention," for the configuration in which a third planet breaks up an enclosure — a planet hemmed in on both sides by two others. The intervention happens when that third planet either steps in bodily, coming between the two enclosing planets, or casts its rays into the degrees between an encloser and the enclosed planet. It is the canceling condition of the enclosure doctrine: an enclosure that an intervention has broken no longer counts.

In Tradition

In the reconstructed Hellenistic doctrine of bonification (helping a planet) and maltreatment (harming one), mesembolesis is the third leg of the enclosure-triad — sign-based containment, degree-based enclosure, and the intervention that cancels either. For an enclosure by two benefics or two malefics to count, those two must be the only planets flanking the enclosed one; a third stepping in, by body or by ray, dissolves it. Brennan notes the rule applies wherever a planet blocks a degree-based aspect.

In Practice

When you judge whether a planet is enclosed — hemmed in on both sides by the two benefics or the two malefics — mesembolesis is the test for whether the enclosure actually holds. You check the degrees on either side of the enclosed planet for a third body, and whether any other planet casts a ray into the space between. If a third planet comes bodily between the would-be enclosers, or sends rays into the gap, the enclosure is broken and does not count as a bonification or maltreatment condition; only unbroken flanking by the two relevant planets registers. You read an intervention as a softening factor when the enclosure would have been by malefics — it rescues the enclosed planet from besiegement — and as a spoiling factor when it would have been protective, by benefics. Brennan observes the rule reaches beyond enclosure: whenever a planet steps into a degree-based aspect, the same logic applies. You weigh it with enclosure and containment.

Historical Origin

Mesembolesis is attested in the Hellenistic technical literature on aspect-doctrine. It is defined chiefly in Porphyry's Introduction to Ptolemy's Tetrabiblos (3rd c. CE) and, to a lesser extent, in the Compendium of Rhetorius of Egypt (c. 6th-7th c. CE). Chris Brennan reconstructs the intervention doctrine and its place in the enclosure-triad in Hellenistic Astrology (2017), and Demetra George records it among the softening configurations in Ancient Astrology in Theory and Practice.

Etymology

Origin: Greek. Meaning: Intervention, interposition.

Definition

In Tradition

In Practice

Historical Origin

Etymology

Further Reading