What is traditionally known as the Temperance card is a reference to the Soul. Classically female, she is mixing up a blend of subtle energies for the evolution of the personality. One key to interpreting this card can be found in its title, a play on the process of tempering metals in a forge.
Metals must undergo extremes of temperature, folding and pounding, but the end product is infinitely superior to impure ore mined from the earth. In this image, the soul volunteers the ego for a cleansing and healing experience which may turn the personality inside-out, but which brings out the gold hidden within the heart. (This card is entitled "Art" in the Crowley deck.)'
It is hard, at first, to see where Sagittarius, the ruling sign of this card, fits in. Sagittarius is an expansive sign and Temperance is, on a surface level, about "tempering." Butler points out that the original pouring from cup to cup might have been about cutting wine with water. So this is a card about moderation. There is, however, another angle to the card, that of merging seemingly impossible opposites. Sagittarius, the centaur, merges beast and man into a unique creature. And then there is the bow and arrow, one moving, one stationary, working together to point the way. Temperance may be, at first glance, a warning to the Querent to "temper" their behavior, to cut their wine with water. But it may also be a reminder to the Querent that seemingly irreconcilable opposites may not be irreconcilable at all. Belief that fiery red and watery blue cannot be merged may be the only thing standing in the way of blending the two. Change the belief, measure out each with care, and you can create otherworldly violet.
This card really does seem to be less about moderation then about the Sagittarian desire to find a unified field theory, a way of blending opposites, achieving synthesis. In a reading, this card can mean that the Querent sees two opposite camps (choices, belief systems, families, friends) and no way to unite them. But sometimes the only reason the two won't blend is that we're not taking the time, not measuring out the right amounts (the Querent might, for example, be trying to merge two full families when blending has to occur bit by bit with individuals). It is also a reminder that a bow and arrow are useless apart, but together a formidable weapon. This card tells the Querent that they CAN and should put thesis and anti-thesis together to get the even more useful synthesis. But it will take time, care, patience and experimentation. And also, yes, moderation.