Vessel
The vessel is central in alchemical processes (which, in turn, were a projection of psychological, unconscious processes), where the Latin word vas was typically used. But this often important symbol naturally appears in many forms in our dreams, alongside the retort, with distinct symbolic significance. Since the vessel is created by humans, its contents are related to the function of consciousness – perhaps a concept, or a way of understanding something.
von Franz says:
“Psychologically, the vessel has to do with promises, ideas, basic feelings, and concepts that we try to hold together and preserve in life, for the vessel can contain these things so that they do not get lost. It thus serves as a means to become conscious.” (Redemption Motifs, p. 28.)
Alchemy
The alchemical process occurs in a carefully sealed vessel (vas bene clausum). For alchemists, the vessel is essentially the feminine expression of the masculine stone – in other words, both are the philosopher's stone. Their highly prized glass retort allowed them to study what was, in fact, (a projection of) their inner process; thus, the vessel is the process itself, sometimes equated with the soul.
Psychologically, the vessel can be an expression of the Self. Alchemists repeat that one should not mix the contents of the hermetic vessel with anything from the outside, as the lapis "has everything it needs." (See also Kitchen.)
The transparent retort allowed the adept to observe what was happening inside, without being directly affected by it, so to speak. This distance and separation hold psychological significance.
“The conscious experiences what happens in the unconscious [complexes, conflicts, etc.], but does not identify with it; a very difficult thing to do but absolutely crucial.” (Mysterium Lectures, p. 82.)
Transformation
That the vessel is a tool for transformation is evident in the ancient mysteries, for example, in the Mithras cult. The alchemist Zosimos urges the adept to “dive into the vessel” to achieve a higher state of consciousness. (Alchemical Studies, par. 96.) “The hermetic vessel” is “the womb of spiritual renewal” (Ibid., par. 97). The Holy Grail is an example of how the vessel itself serves as a means of transformation.
It is a common theme in dreams that what is enclosed transforms and comes out as something different.
Heat
Since the process requires heat, the oven is a typical symbol for the vessel in these respects, but it could be any kind of container. In the I Ching, the “Cauldron” symbolizes the technique for creating the new human; according to traditional yoga, one must be “cooked” to achieve enlightenment. (See also Fire.) This image is similar to the widespread motif of the hero being swallowed by a monster, only to return as reborn (sometimes with burned hair, emphasizing the necessity of heat and symbolizing the bald head of the newborn).
Jung says that whenever the cauldron appears, it represents transformation, the alchemical process. The “bad” is placed in the cauldron to be boiled and transformed into something good. (Visions, pp. 562f.)
Private Content
Like the alchemical process, psychological development benefits from slow processing in a private space. The vessel serves as a magical protective ring and a barrier against external influences. (See also Circle.) Jung spoke of temenos, the sacred space, as a metaphor for the need for the private sphere as a place for processing (e.g., the therapeutic setting). When one openly shares inner experiences, especially spiritual or intimate ones, it often leaves a void behind; there are often reasons to keep some experiences to oneself so they are not lost, or at least to ensure a safe temenos where narration and processing can occur, let’s say, in secrecy. However, the effects of the processing are carried out into everyday life – it is not about isolation; on the contrary, only those who understand themselves can have a true relationship with others.
Spillage
Related to the above, “spillage” is closely tied. The motif of spilling something is almost certainly negative. In a dream, perhaps a glass breaks and the liquid spills on the floor, one accidentally knocks over a cup, or spills food on oneself. It could symbolize a lack of an adequate “container” for the content or mishandling of it. Characteristically, what is spilled is lost; it is rarely possible—or desirable—to return it to the vessel. The spilled liquid lies as a stagnant puddle on the floor, a symbol of something lacking energy, direction, and so on.
Put Something Away
Placing something in a container and sealing it (a bottle, box, etc.) can also symbolize putting something away as a “nothing more than.” If something bothers us—an emotion, a guilt, or a phenomenon we don’t understand—we might put it away, lock it up in a box; we intellectualize and move on. We attempt to put the genie back in the bottle to leave the mystery behind, avoiding the burden. (Compare Name.)
But putting something in a box and moving on can also refer to a lack of patience, perhaps with a challenge; one moves to the next challenge instead—one that might also be put away and left behind. In this way, one might live a “temporary life,” not dealing with things that could benefit one’s development.
Hide Something
Symbols always have two sides. The image of “putting something away” doesn’t necessarily imply something negative. The sacred may be something we wish to keep as a secret, as if the gaze of the world would destroy it; a psychological truth mentioned earlier. For example, as a child, Jung kept a small figure in a box hidden in the attic, which he turned to for support when life felt difficult. The secret marked, as he writes in his autobiography, “the height and conclusion of my childhood” (Mitt liv, p. 34).
Container with Food
In mythology, folk tales, and mystery cults, the vessel is often a container for nourishing food. As such, it is typically offered by a woman. For example, Idun is usually depicted with a bowl or basket of the apples of immortality; in the Eleusinian initiation, the female guide carries a vessel with the elixir of immortality; the mystery goddess at Lycosura carried a basket with the objects of the secret ritual; Demeter is depicted with the “mystery basket”; Epona sits with a basket in her lap surrounded by horses, and so on.