Beanu: Yes, of course you may use my argument, thanks for asking. A little footnote would be nice. How do I get you my full name? If I think of any more arguments, I'll let you know. And the philosopher who talked about the two halves searching for each other was Plato in the Symposium, the speech by Aristophanes (see Wikipedia). It's not clear if Plato is serious or not.
Kwaw: You bring in a Sufi interpretation of Plato's image of the sun to clarify your correlation of the sefira of the Sun to the Pope! You're making me work. I felt the need to read the thread on "Plato and Tarot," which turned out to be less on Plato than on Kabbalah, with a lot by Beanu and Kapoore relevant to the discussion here. Then I had to read Kwaw's links to other threads on Plato. Kwaw, I really like your posts. I only think you give in too easily (I for one still think the Cary-Yale is 1451 or so. If the coins were issued in 1447, all that shows is that the deck wasn't earlier than then. It still could be later. Sforza was making a huge propaganda effort to link himself with the former regime; since the cards have holes in them, they may have been on display for the nobility.) And then I had to brush up on my Plato.
I see plenty of Platonic thought in the Zohar but not imagery, which is mostly biblical. One reason Tiferet is associated with the Sun is that the Beloved in the Song of Songs has solar imagery, especially the sun at dawn or dusk. "My beloved is ruddy and white..his head is as fine gold." And: "My beloved spake and said...the winter is past, the flowers appear on the earth..." More indirectly: "he cometh leaping upon the mountain and skipping upon the hills..he looketh forth at the windows, showing himself through the lattice." And the Shulamite is the dark of the moon: "I am dark but comely."
The Sufis certainly did combine Platonic and Biblical imagery, even back then. But I doubt if the 15th-17th century tarot designers read them. It's possible, as France and Turkey were allies in the 16th century; I just haven't heard anything.
The tarot designers did know their Hebrew Bible and their Plato, from the beginning. Philippo Sforza's secretary Decembrio translated the Republic (Trionfi website). Other of Plato's works must have been well known. In the Pierpont-Morgan-Bergamo Chariot card, you can see the wings on the horses, I think a reference to the myth in the Phaedrus.
So here's some Plato on the sun and beauty (Kapoore, you will perhaps be more at home here):
508b-c: "..it is the sun which I called the offspring of the Good, which the Good begot as analogous to itself. What the Good is in the world of thought in relation to the intelligence and things known, the sun is in the visible world, in relation to sight and things seen."
508e: "Both knowledge and truth are beautiful, but you will be right to think of the Good as other and more beautiful than they."
Then comes is the Allegory of the Cave. We live in a cave and mistake the shadows cast on the wall by cutouts between it and a fire for real things. If someone turned us around and dragged us out, we would see that the cut-outs were just imitations and the fire wasn't really the sun. The light of day would pain us, and we'd have to look first at reflections in the water, then the night sky, and finally the true sun. Then if we returned, the cave would seem like a prison to us. Thus:
517b: "...The realm of the visible should be compared to the prison dwelling, and the fire inside it to the power of the sun. If you interpret the upward journey and the contemplaton of things above as the upward journey of the soul to the intelligible realm, ..in the intelligible world the Form of the Good is the last to be seen, and with difficulty; when seen it must be reckoned to be for all the cause of all that is right and beautiful..."
I am quoting the Grube translation, but I give the standard page references so you can look it up on-line if you want.
Another famous place where beauty is discussed is in the Symposium. It distinguishes several levels of love for the Beautiful (in the speeches of Socrates and Alcibiades). Here are the main ones. There is carnal desire for beautiful bodies, e.g. Alcibiades. There is Alcibiades' desire to know the beautiful soul of Socrates (intellectual love). And there is Socrates' love for his own muse, Diomida, seen in an ecstatic vision. One is in the Cave, one is the process of going outside, the third is seeing reality, if only its reflection in the water.
It strikes me that these three objects of love also have three versions of the sun. One, beautiful bodies, corresponds to the pretend-sun, the fire in the cave. It is the "central sun" of the Pythagoreans and the "central fire" of the alchemists, deep in the heart of the earth. It is what lights the Devil card. Even though in the Zohar Satan orginates in the 5th sefira, it makes sense to put in him in the 6th, the center of his infernal Tree, surrounded by his minions, the vices (if I understand Kwaw correctly).
The process of enlightenment is something else. The Pope card is one candidate, pointing upwards.
Third, the reflection of the sun in the water, and its indirect perception as its light hits other things, like the Moon.
To these a fourth can be added: the sun itself.
Some of Plato's last words on beauty are in the Phaedrus. A charioteer leads two horses, one dark and undisplined, the other light and noble. The undisciplined one sees a figure off in the distance and is seized with a desire to possess it sexually, by force if necessary. The noble horse cannot restrain it until they get close enough for the rider to make out that it is Beauty, whom he recognize from a long time before, when the horses had wings and he'd seen it in the distance. The rider's words give extra strength to the noble horse, and between them they manage to halt the ignoble horse. They stand in awe, and the horses begin to regrow the wings they had lost in descending to earth.
It strikes me that the Noblet Chariot card captures very much the imagery of Plato's account. One is dark, the other light (see the original card, on Flornoy's website). There are no reins, so it must be by words that the rider communicates his wishes--and only the noble horse listens to them. Both horses look the same way, although their feet go in opposite directions (this feature occurs as early as the Cary Sheet). They are looking at Beauty. One horse is Reason, the discipline of dialectic, the other Desire. Both are needed for the three to behold Beauty. The rider himself is speech, the Word.
This rider seems to me a fit candidate for Tiferet. He is young and beautiful, like the Beloved of the Song of Songs. This Beloved, as Solomon, is also said to build a chariot (SofS 3:9). In the "supernal palaces" section of the Zohar, Tiferet is located at the lips, the place of speech. The Marseille chariot is not a war chariot; it is a parade chariot, displaying Beauty (like a parade float) or a victorious quest to behold it. The horses are, in one way of looking at them, Netzah and Hod. I tend to see Netzah as the noble horse, the Hermit, and Hod as the ignoble one, the Wheel, representing the instability of matter.
Netzah was known as Endurance and Eternity, both of which fit the Hermit. He carries the lantern of Diogenes, the philosopher who on the d'Este Sun card (see Beinecke Library website) is telling Alexander the Great to stop blocking his sun, i.e. trying to corrupt him by offering him the position of court-philosopher. The Conver card associates him with old Hermes Trismegistus, in that the spelling changes from "Ermite" to "Hermite." His planet would be Saturn, as described by Ficino in "Three Books on Life."
Fortune is the fickle "Aphrodite Pandemos" of the Symposium, the people's Venus. Hod was known as "Splendor" and "Majesty"--the allure of fame and fortune. It often results in a fall (as in the fall of Phaeton from his chariot on the "tarot of Mantegna" Sun card). Pico's quest for Truth ended in such a fall, clashing with the real-life Pope (at the top of the Wheel), who saw the threat to his hierarchy's power. Thus Pico had plenty of time for prayer and confession. (Kwaw, your epithets for these three sefiroth were really interesting; I just would like to know their source and if they were well enough known in the 15th-17th centuries. Mine come from Scholem, The Kabbalah.) We are in the descent, and the soul has now fallen to the level of Yesod.
In another way of seeing the Chariot, the horses are Gevurah and Chesed, strict Justice and lenient Love (violent Mars and noble Jupiter). The Charioteer, victorious not in war but in beauty, shows Mercy. Similarly, Francesco Sforza, husband of beloved Bianca, was elected duke of Milan without a battle.
The Chariot is at ground level: the horses don't have wings. If it is the sun, it is at dawn or dusk, when it is close to the earth. (You see, Kwaw, I like your attribution of "earth" after all.)
As for the Pope card, well, I see him up there with the noonday sun, in Pico's Empyrean, the place Dante put God (and I put the Upper Sun; similarly the Neopythagorean identified the Monad with the Sun, and Kwaw the Magician, although at the bottom). But the Pope does not see the sun itself, only a reflection of it. He and his hierachy the Church are the bridge between the planets and the upper world, where he might be Malkhut, the "supernal earth" (another earth-attribution). Real Popes sometimes even descend on the Central Pillar to the level of the Devil. It is easy to mistake images and fires for the genuine article.
So that's my thought, after reading Kwaw and Beanu. And I don't mean it in opposition to theirs, just as another version, which I like better.