I understand your thought process. However -
How would you be able to measure 5% of difference between those different elements of Mercury? How would you be able to isolate the various other considerations that are having an effect on Mercury? Why 5% anyway? Why not 12%? Why not 14.57% Why does it have to be a real number?
And the time sensitivity thing is one of the reasons why that elemental "rule" looked iffy. And why the ascendant and moon were also looked at for mental/character delineation all these years.
Also, I think due to the immense amount of syncretism during astrology's development that what we get is a mishmash of different traditions surviving to this day - some of which are totally at odds with one another. I don't personally know how relevant or useful planetary friendships are to delineation when it actually matters.
"I have been looking at legendary scientists or just those that are said to have a high IQ, this is what I have found.
3rd house mercury in gemini or aquarius.
eg thomas edison and nikola tesla has a third house mercury
thomas edison mercury in aquarius and nikola tesla mercury in gemini
Ung Yong Kim has mercury in aquarius
Mercury conjunct saturn
I know I was surprised too, but a lot of them seem to have this aspect.
eg Nikola Tesla, Albert Einstein, Ung Yong Kim(said to have the highest IQ in the world-has a lot of achievements at an early age)
Isaac Newton has the square between mercury and saturn. Stephen Hawking has the trine.
This one I was really surprised because of the fact that capricorn is not always a sign associated with intelligence. But then again saturn is the co-ruler of aquarius and also this could mean that they have the ability to discipline their minds to actually learn, unlike gemini and aquarius energies that activate curiosity and progressive ideas.
Mercury in aspect to uranus-which is no surprise there.
eg Stephen Hawking, Ung Yong Kim, Benjamin Yantanyahu(said to have a high IQ, Albert Einstein had the inconjunction. Thomas Edison who did not have mercury in aspect to uranus, had mercury in aquarius.
There also seems to be 3rd house and 10th house activity. Which comes to no surprise(3rd house being the house of gemini and 10th house being the house of careers -and many of them are in 'smart' fields)
10th house mercury-albert einstein. Benjamin Netanyahu. (including him does not convey my thoughts and opinions about the israel-palestine issue-so I don't want to hear comments about that-this is not political)
Mercury also aspects the ascendent or the sun.
I have observed actors and actresses said to have a high IQ-they didn't have these markers-reason for that could be because they didn't enter scientific or revolutionary fields.
So to sum it off, I think whatever aspects the mercury influence the way you think or learn. However, unless you have 10th house mercury energies, or even prominant aspects from mercury to sun, ascendent, you will not be KNOWN for your intelligence or become a famous scientist/mathematician
For those of you that have mercury with saturn, uranus, and with whatever else planet, one of your goals in this life time here is to learn how to learn effectively in regards to that planet.
For example, mercury-uranus-learn to apply what you learned to the real world-and form ideas of how this knowledge can be used, be creative with it. Maybe convey and teach the content to others in a very eccentric ways with interesting imaginary stories related to the content.
Mercury-mars-application, hands on, how you actually apply the information that you learnt.
Mercury-neptune, make a story, us imagination to form a story that relates to the content/information
or roleplay
"
Merury-saturn-plan how you are going to study, repeatedly memorize the content that you must know, but also form connections to words that will help you remember things better. Also learn how to discriminate and undergo the process of elimination when you need to like in the case of multiple choice questions.
-This is a thread I created earlier
As you can see, many of the greatest scientists had mercury in gemini, or aquarius, mercury with saturn/uranus, and a 3rd house emphasis so for me it only seemed intuitive that mercury in those signs would create intelligence.
But I've also seen an occurence of people with high iqs that don't do innovations in science, to have mercury in other signs. Also what was the basis of older astrologers claiming that certain signs produce more intelligence?
Now mercury in pisces is quite the finding and I one hundred percent agree with you. But the findings still baffle me how what's seen as naturally intelligent does show up, but also what's seen as 'dumb' also shows up in some ways or the other.
For example, the quintile seems to be a sign of talent, uranus is considered the higher octave of mercury, and it's innovation. Mercury is one part of the mind at least and it being quintile uranus definitely as a sentence reads as this person will have an innovative mind. And this aspect does show up in fact in geniuses. However, so does what's deemed as weak/debilitated.
I find that amusing and odd and I wish I could find an explanation lol.