In The Interpretation of Dreams (1900a), Freud wrote, "There is often a passage in even the most thoroughly interpreted dream which has to be left obscure; this is because we become aware during the work of interpretation that at that point there is a tangle of dream-thoughts which cannot be unraveled and which moreover adds nothing to our knowledge of the content of the dream. This is the dream's navel, the spot where it reaches down into the unknown" (p. 525).
This careful formulation seems to contradict Freud's whole approach to analyzing dreams, which is to take the analysis as far as possible. As he later wrote when discussing the Wolf Man's dream, "It is always a strict law of dream interpretation that an explanation must be found for every detail" (1918b, p. 42n).
It is therefore unsurprising that Freud, rather than accept "the unknown" as a barrier, should wonder whether a given patient's resistance indicated failure stemming from the inadequacy of the analyst or of the analytic method themselves. In "Notes on Dream Interpretation" (1925i) he returned to the issue, pondering "the limits to the possibility of interpretation of the interpretable" (p. 127). There he stressed, "Those dreams best fulfil their function [to satisfy a wish in spite of the ego] about which one knows nothing after waking" (p. 128) or that are quite simply forgotten. They therefore appear to be uninterpretable. All the same, "it sometimes happens, too, that after months or years of analytic labour, one returns to a dream which at the beginning of the treatment seemed meaningless and incomprehensible but which is now, in the light of knowledge obtained in the meantime, completely elucidated" (p. 129).
See also: Analyzability; Incompleteness; Over-interpretation; Real, the (Lacan); Surrealism and psychoanalysis.
Dadoun, Roger. (1972). Les ombilics du rêve. Nouvelle revue de psychanalyse, 5, 239-254.
Freud, Sigmund. (1900a). The interpretation of dreams. SE, 4: 1-338; 5: 339-625.
——. (1918b). From the history of an infantile neurosis. SE, 17: 1-122.
——. (1925i). Some additional notes on dream interpretation as a whole. SE, 19: 123-138.
Rosolato, Guy. (1978). La relation d'inconnu. Paris: Gallimard.