I stumbled onto something truly astonishing about the Fool. It may have been talked about before, but if so I missed it.
I've always thought of the Fool as the soul about to take a leap into the material; but I believe this is completely backwards. He's the soul, or spirit—however you want to look at it—but he's already in the material plane and about to take a leap into the spiritual. There are several reasons why I think this is the case.
1) He's carrying a staff and wallet. These are items necessary on the material plane.
2) Waite's language in the PKT describes him as already in the world:
"With light step, as if earth and its trammels had little power to restrain him, a young man in gorgeous vestments pauses at the brink of a precipice among the great heights of the world;"
He among the great heights of the world, but in the world even so.
"He is a prince of the other world on his travels through this one. . . ."
3) In Waite's 1909
Occult Review article "The Tarot—A Wheel of Fortune," he says:
"On the spiritual plane it is the soul, also at the beginning of its experience, aspiring towards the higher things before it has attained thereto."
If the Fool is the soul abiding in the world of spirit, why would he be "aspiring towards the higher things?" That's something you do if you're in the material plane.
4) Waite has followed Levi in respect to number (0); placement (next to last in the series); and most importantly the Hebrew letter Shin. If you look closely you'll see
Shin superimposed over one of the wheels on the Fool's tunic. This is important because it clearly places the Fool on the path of Shin.
5) If you put the Fool on the Tree looking toward the path of Shin, as in
this image, some things start to make sense. The Fool is seen "aspiring toward higher things" per Waite's description. Also, the sun in Tiphareth is seen exactly where you would expect it! It's interesting that Waite describes it as "the sun." Many have made the argument that it's actually Kether, but in this scheme it can be seen it really is the sun. Waite says something else that starts to make more sense in light of this arrangement:
"The sun, which shines behind him, knows whence he came, whither he is going, and how he will return by another path after many days."
The path of Shin is not the way he will return. It will be straight up to Yesod, then Hod, Netzach, etc. But mainly I think it refers to the middle way on the central pillar. (It says he'll return by another "path" not "paths.") The Fool has aspiration, but he doesn't as yet seem to have a plan.