英：moebius strip; 法：bande de moebius
莫比乌斯带是拉康在其对于拓扑学 (TOPOLOGY)的使用中所研究的众多图形之一。它是一个三维图形，可以通过拿取一个长条的矩形纸带并且将其扭转然后再将其两端接合起来而构成 (见：图9)。结果便是这一图形颠覆了我们表现空间的正常（欧几里德式）方式，因为它看似具有两个面，但其实只有一个面（而且也只有一条边）。就局部而言，在任何一点上，两个面都可以清楚地加以区分，但是当沿着整条纸带经过时，两个面就会明显变为实际上是连续的。两个面只能经由时间的维度来加以区分，即通过沿整条带子经过所需花费的时间。
这个图形阐明了精神分析问题化各种二元对立的方式，诸如内部/外部、爱/恨、能指/所指、真理/显象，等等。尽管这些对立中的两项往往皆被呈现为截然不同的，然而拉康更喜欢根据莫比乌斯带的拓扑学来理解这些对立。因而，这些对立项便不是被看作离散的，而是被看作彼此连续的。同样，主人话语与分析家话语也是连续的。
莫比乌斯带还有助于我们理解“穿越幻想”(traverse the fantasy)是如何可能的 (S11,273)。只有两个面是连续的，才有可能从内部穿越到外部。不过，当我们用一根手指沿着莫比乌斯带的表面绕行的时候，我们便不可能说出我们是在哪一个确切的点上从内部穿越到了外部（或者反之亦然）
(bande de moebius) The moebius strip is one of the figures studied by Lacan in his use ofTOPOLOGY. It is a three-dimensional figure that can be formed by taking a longrectangle of paper and twisting it once before joining its ends together (see Figure 11). The result is a figure which subverts our normal (Euclidean) way of representing space, for it seems to have two sides but in fact has only one (and only one edge). Locally, atany one point, two sides can be clearly distinguished, but when the whole strip istraversed it becomes clear that they are in fact continuous. The two sides are onlydistinguished by the dimension of time, the time it takes to traverse the whole strip.
The figure illustrates the way that psychoanalysis problematises various binaryoppositions, such as inside/outside, love/hate, signifier/signified, truth/appearance. Whilethe two terms in such oppositions are often presented as radically distinct, Lacan prefersto understand these oppositions in terms of the topology of the moebius strip. Theopposed terms are thus seen to be not discrete but continuous with each other. Likewise, the discourse of the master is continuous with the discourse of the analyst.
The moebius strip also helps one to understand how it is possible to 'traverse thefantasy' (S11,273). It is only because the two sides are continuous that it is possible tocross over from inside to outside. Yet, when one passes a finger round the surface of themoebius strip, it is impossible to say at which precise point one has crossed over frominside to outside (or vice versa). (mere) In Freud's account of the OEDIPUS COMPLEX, the mother is the first love object of the child; it is only the intervention of the FATHER, via the threat of castration, which forces the child to give up his desire for the mother. Inthe work of Melanie Klein, the emphasis shifted from the role of the father to thepregenital mother-child relation; the latter was described as a sadistic relation in whichthe child makes (in fantasy) vicious attacks on the mother's body and then fearsretaliation from her.