Al Biruni's prevention: meaning of "equal degrees"

1
Hello, this is my first post in the traditional forum.

Suppose we have a configuration like this:

Moon 23'22 Taurus
Jupiter 23'57 Capricorn
Venus 24'14 Taurus

I wonder if Al Biruni would say Juptier prevents the conjunction. Does the phrase "if their degrees are equal" in the passage below mean both planets must be within 23 degree, for example, or can we take it to simply mean within 1 degree?

The difference being: if Moon in 23 and Venus in early 24 are not in "equal degrees" in Al Biruni's definition, Jupiter in late 23 will prevent by being closer to Moon. If, however, Moon and Venus are considered in "equal degrees", then their partile conjunction is an "advantageous" aspect that renders Jupiter's trine with Moon ineffective: and therefore Jupiter cannot prevent the conjunction.

I am not sure if I understand the passage properly to start with, so if my question s mistaken in the first place, please be so kind as to correct me!

Quote: Al Biurini on "Prevention", The book of instruction on the elements of the art of Astrology:

"When there is a third planet in a sign between the inferior and superior ones, it prevents the conjunction of the former with the latter until it itself has entered into conjunction. Then two planets tend to form a familiarity with a third at the same time, the one by means of corporal conjunction, the other by aspect, the former renders the latter vain if their degrees are equal; but when their degrees are different, and the one casting the aspect is nearer to completion than the one tending to conjunction, the former is preferred... Certain aspects must have an advantage over others, just as corporal conjunction has over aspect, so that the more powerful aspect should interfere with the weaker, but astrologers have not pronounced on this matter."

(Page 506, London:1934, digitalised by Antioch Gate ebooks, 2007)

2
Hello Amelia,

Not sure if this will be helpful or correct but on this link as it seems to refer to horary astrology.
https://www.skyscript.co.uk/tobyn2.html
Graeme Tobyn explains

"It is as if our authors rather ask themselves 'who is closer to whom?' than 'who will get there first (in time)?' It is likely that planetary tables 1000 years ago were less reliable and astrologers looked more to the spatial arrangement of planets in the horoscope than to the temporal arrangement in the timing of sequential aspects which were difficult to calculate but which we today are easily able to follow in an ephemeris. Al-Biruni gives the same two forms of Abu Mash'ar's prohibition, but calls this form 'prevention'. He uses the phrase "nearer to completion" to denote the greater closeness of the interposing planet to the receiving significator, which may indicate a spatial or a temporal measurement. Schoener and Dariot also reproduce these two forms of prohibition, and speak of "nearer to conjunction" or aspect."
In your example, Moon and Venus are significators and it is a question of which one (The Moon or Jupiter) will get first to Venus.
With the explanation of Tobyn, it would be something like this:
Jupiter conjoins Venus first and "does not stop prohibiting the conjunction of the Moon with Venus until he passes Venus and separates from him. The Moon applies to Venus from the time that Jupiter has passed him"

Hope other people have the same or a better understanding of the matter.

Kind regards,
Ouranos
Blessings!

3
amelia s... interesting question... it sounds like a horary type quiz as i read it..

i would only like to point out the use of the words inferior and superior in the quote you give is related to the inferior or superior planets as i understand it... inferior being venus, and mercury, while superior are mars, jupiter and saturn... so in your example if you arranged it differently where venus was in cap and jupiter was in taurus, i think the quote would apply more readily.. "When there is a third planet in a sign between the inferior and superior ones" is the quote i am trying to appreciate...

the term ben dykes uses for prohibition is 'barring' or blocking...i recommend the book 'introductions to traditional astrology' abu ma'shar and al-qabisi - ben dyke translation.. see page 160 to 163... he discusses this more at length..

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From the context, it seems more likely to me that the words translated here as 'inferior' and 'superior' refer to the swifter (applying) planet and the slower planet (being applied to), respectively. Of course these may often be an inferior and a superior planet, respectively, in the sense mentioned by James, but other possibilities exist.

Regarding Amelia's question, the crux of the matter seems to be how exactly al-Bīrūnī would have defined 'equal'. My guess (which is all it is, based on the general tenor of medieval Perso-Arabic astrology) is that anything within one degree (60 minutes of arc) would have counted as being in the same degree, or 'equal'. But it is many years since I read al-Bīrūnī (in translation). As James says, it may be useful to compare him with other authors on the same topic, such as Abū Maʿshar, al-Qabīṣī, Sahl ibn Bishr, and Abraham ibn Ezra.
https://astrology.martingansten.com/

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Ouranos, thank you. So medieval astrologers think that the heaviest planet (the receiving significator) prefers whatever planet standing fewer degrees away from him, disregarding planetary speed and temporal movement. If same distance, conjunction is preferred to other aspects.

What I found most interesting is this: they don't seem to concern themselves with the fact that the applying significator may meet the interposing planet somewhere. What does this mean? It means that if Venus and Saturn are significators in an applying aspect, the fact that Mercury (in fewer degrees than Venus) might overtake Venus and meet Saturn first, simply does not matter. Saturn still prefers Venus because Venus is closer to him to start with.

If both the applying significator and interposing planet are same distance (say 5 degrees) away from the receiving planet, and by the same aspect, the receiving planet gets to decide whose rays he will receive again (!), this time by reception. Planetary speed and movement, again, have no role to play!

I share Martin’s instinct on what Al-biruini meant by equal degrees (glad to have your input) and at James’ suggestion (THANK YOU!) I have checked out Mr Dykes’ work. I understand that both Abu Ma’shar and Al-Qabisi agree with Al-biruni: that is, we will prioritise conjunction if the three planets concerned are in equal degrees.

Dykes' book section on barring is very clear and helpful, but since I couldn’t elicit a definition of equal degrees from the book, I have written to Mr Ben Dykes himself for advice. We'll see if he got my letter alright.

In gratitude,
Amelia

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Kind and thoughtful James - hope you get my PMs. I suspect one of my messages didn't get through. If you have only received one please let me know.

Thank you truly,
Amelia