The living symbol formulates an essential unconscious factor, and the more widespread this factor is, the more general is the effect of the symbol, for it touches a corresponding chord in every psyche. Since, for a given epoch, it is the best possible expression for what is still unknown, it must be the product of the most complex and differentiated minds of that age. But in order to have such an effect at all, it must embrace what is common to a large group of men. This can never be what is most differentiated, the highest attainable, for only a very few attain to that or understand it. The common factor must be something that is still so primitive that its ubiquity cannot be doubted. Only when the symbol embraces that and expresses it in the highest possible form is it of general efficacy. Herein lies the potency of the living, social symbol and its redeeming power. [821] All that I have said about the social symbol applies equally to the individual symbol. There are individual psychic products whose symbolic character is so obvious that they at once compel a symbolic interpretation. For the individual they have the same functional significance that the social symbol has for a larger human group. These products never have an exclusively conscious or an exclusively unconscious source, but arise from the equal collaboration of both. Purely unconscious products are no more convincingly symbolic per se than purely conscious ones; it is the symbolic attitude of 657 the observing consciousness that endows them both with the character of a symbol. But they can be conceived equally well as causally determined facts, in much the same way as one might regard the red exanthema of scarlet fever as a "symbol" of the disease. In that case it is perfectly correct to speak of a "symptom" and not of a "symbol." In my view Freud is quite justified when, from his standpoint, he speaks of symptomatic 84 rather than symbolic actions, since for him these phenomena are not symbolic in the sense here defined, but are symptomatic signs of a definite and generally known underlying process. There are, of course, neurotics who regard their unconscious products, which are mostly morbid symptoms, as symbols of supreme importance. Generally, however, this is not what happens. On the contrary, the neurotic of today is only too prone to regard a product that may actually be full of significance as a mere "symptom." [822] The fact that there are two distinct and mutually contradictory views eagerly advocated on either side concerning the meaning or meaninglessness of things shows that processes obviously exist which express no particular meaning, being in fact mere consequences, or symptoms; and that there are other processes which bear within them a hidden meaning, processes which are not merely derived from something but which seek to become something, and are therefore symbols. It is left to our discretion and our critical judgment to decide whether the thing we are dealing with is a symptom or a symbol. [823] The symbol is always a product of an extremely complex nature, since data from every psychic function have gone into its making. It is, therefore, neither rational nor irrational (qq.v.). It certainly has a side that accords with 658 reason, but it has another side that does not; for it is composed not only of rational but also of irrational data supplied by pure inner and outer perception. The profundity and pregnant significance of the symbol appeal just as strongly to thinking as to feeling (qq.v.), while its peculiar plastic imagery, when shaped into sensuous form, stimulates sensation as much as intuition (qq.v.). The living symbol cannot come to birth in a dull or poorly developed mind, for such a mind will be content with the already existing symbols offered by established tradition. Only the passionate yearning of a highly developed mind, for which the traditional symbol is no longer the unified expression of the rational and the irrational, of the highest and the lowest, can create a new symbol.
— Carl Gustav Jung
Jung draws a line here that cuts through the entire psychotherapeutic tradition: the difference between a symptom and a symbol is not a property of the thing itself but a decision made by the observing consciousness. The red rash is data or it is disclosure, depending on how you face it. That is not relativism — Jung is precise about the conditions. A symbol requires the collaboration of conscious and unconscious in roughly equal measure; it must carry what is most primitive in a group while expressing it in the highest available form. Pull either end away and you are left with a sign, a symptom, a convenient flag for a known process.
What goes unspoken in the passage, but pressures every sentence, is what it costs to live in the symbolic attitude rather than the symptomatic one. The symptomatic reading is the cheaper option — you name the cause, close the case, preserve the sense that the psyche is a mechanism you have already mapped. The soul-material disappears into the diagnosis. The symbolic attitude holds the not-yet-known open and refuses to cash it out early. Jung places that refusal at the edge of a highly developed and passionately yearning mind, which is a way of saying: most of us, most of the time, prefer to know what we are dealing with. The symbol survives precisely because that preference fails to exhaust it.
Carl Gustav Jung·Psychological Types·1921