Many interesting things surround the problem of the "missing virtue": Whether prudence is missing at all (some refer to the Plotinian three virtues, omitting prudence)? Whether it is hidden behind the face of one of the trumps (Popess, Hermit, Hanged Man and World have been suggested)? Whether prudence is the same as Wisdom (theology; e.g. Thomas Aquinas, does deny this)? Whether it clings together with providence (which is true)? I admit, I don't know for sure. But there are some considerations my reflecting on these problems has brought up:
1. If 'prudentia' is related to 'providentia', it does not just mean "foreseeing" in time, but, as the word (and its respective theology of the middle ages) does imply: "care" or "taking care of someone." It is a warm notion of God's healing presence, even if it means to die…This seems also to be related to the old myth of "Pro-Meteus" – "the one looking forward" "taking care of things in due and at the right time." As we know, he has stolen the fire to "taking care" of and in promoting humanity. If one does so, the God's will grow angry. Here is a parallel with Genesis's Tree of Knowledge and the wise serpent…
2. While in theological disputes 'prudentia' was considered as low, purely human virtue of "taking care of things at the right time and with foreseeing its consequences," Wisdom, 'sapiantia' (Sophia) was indeed too high to be considered a human virtue. On the contrary, it was seen as even higher than the three "theological virtues," which are named this way to indicate that they are given by God's grace alone. Wisdom, in Christian theology was, of cause, as in John 1, the Logos Himself or, as in Proverbia 8, Sophia Herself, an Trinitarian person or God's female nature and, hence, an essential expression of Godself.
3. Given these facts, it seems not unnatural not to depict Sophia herself, except at the extraordinary place that finalizes the whole journey of the trumps: the World. Indeed, in depicting the 'anima mundi' in the TdM, from a certain time on, this trump was the natural place of the Divine wisdom.
Indeed, Gareth Knight has pointed to the Charles VI-deck regarding the (exclusive) similarity of the three virtues and the World (their cloths, but especially their halo). Interestingly, he was not the first doing so. A year earlier, the book of John Sheppard on the Tarot (I haven't got it with me, so I can't give the title right now), I think it was published 1985, has pointed out this relation. Knight, however, goes a step further in relating these trumps not to the virtues alone but to the four elements and, hence, to a missing link to the four suits. He has done well, I think, in relating Justice's sword to Swords, Strength's column to Staves, Temperance's vessels to Cups, and the World's coin to Coins.
Two questions arise: 1. Is there also a relation of the four virtues to the four elements – I think of the four temperaments as mediator… 2. Does the Divine wisdom relate rightly to "World" or "New Jerusalem" or "anima mundi" or "Earth"?
To only add a further thought on the second question: If Earth is the highest manifestation of Wisdom in the Tarot, could that be related to the tenth sephirot – notably seen as (fallen) Sophia - or any similar Gnostic myth, especially in Basilidean lore? At least in Jewish (not just Kabbalistic) theology, man's journey ends in Wisdom…
Finally, if this difference between prudence and Wisdom holds: why – still – is prudence missing?
Cordially,
Yatima