Coeducation was one of the major transformations of the education system in this century. A major issue is whether it leads to a better understanding between the sexes or rather brings them into conflict. The French Third Republic continued the tradition of separate schools for the sexes that it inherited from the Church, in preference to the American 'coeducational' system. Coeducation was introduced in stages to France only after the Second World War, following women's emancipation. However, whereas the debate at the beginning of the century between the proponents and adversaries of coeducation was based on preconceived socio-political ideas, the late introduction of coeducation was made law without any educational goal or explicit debate. For this reason pernicious inequalities still persist and call not for idealism but for a debate on the ethical and political measures that need to be taken to make equal opportunities between boys and girls a reality.

Psychoanalytic experience and thought is used in this paper to provide an anamnesis that searches for meaning in the midst of 'perceptible' memories. While separate high schools for girls leaves the terrain of sexuality fallow and, at the initiation of the latent phase, contributes to 'epistemophilia', during adolescence this terrain is left 'uncultivated'. Separate schools lead to an idealisation of the opposite sex which is doomed to bitter disillusionment. Today we know that learning together doesn't prevent learning as such. Coeducation provides 'real' companionship but also engenders other effects. With or without coeducation, the relationships between the sexes must be constructed.

Adolescence is a problem period both in educational terms and for researchers trying to understand it. At a time when Freudian thought was being developed, Granville Stanley Hall and his co-workers at Clarke University were working in this field and put forward the concept of genetic psychology. According to this theory, adolescence is the time when childhood comes to an end, the individual enters into the flow of the wider world of humanity as a whole and discovers spirituality. It is a time of opening up and also one of conversions. Female puberty is thus described as a woman's discovery of her physical and spiritual place in the 'chain of life', which transcends the individual.

Rousseau, in Emile, gave roles to Emile and Sophie in the belief that the human race was a single entity. The shortcomings of this search for characteristics, the conclusions of which shock our modern way of thinking, can in fact be found in certain currents of contemporary feminist thought. Thus the use of the word gender since the 1970's, which is supposed to transcend the biological determinism of the term sex, has in fact numerous ambiguities that derive from the difficulty in conceptualising both universality and difference and to the aporia according to which we cannot live without images - that turn out to be false. 'Gender' doesn't exist as such but has to be constructed, painstakingly and through role playing.

Publicity images notwithstanding, nothing is pure in nature. Mixing and blending gives rise to order - in its oldest sense, meaning the opposite of chaos - and innovation. Whether conceived of as geometrical figures or a qualitative explanation, for the ancient Greeks the cosmos was considered to be an infinite variety of harmonious combinations between a finite number of elements. While the Greek city was always based on exclusion, Rome was founded on heterogeneity. This philosophy is reflected in contemporary composite materials. Developing them requires that heterogeneous groups work together and this 'multi-material' culture could be an inspiration for the concept of a composite society, a transposition to the social context of the possibilities of mixing.

Within the concept of a mixed society there are elements of both a hierarchical and an egalitarian system. According to entitative metaphysics, the fact that both sexes belong to the human race doesn't exclude the commensurate and hierarchical differentiation of gender. With the demands for equality of the sexes, universality dissolves as the boundaries fade. Mixed society becomes a question of plurality, of relationships, of exploring the boundaries that constitute the individual, of competition that requires compromise. These are questions of tolerance rather than complementarity.

Plato criticised democracy on the grounds that it was based on desire and so was without limitations. According to this, desire and equality are incompatible. The question posed is indeed how to find a modus vivendi between subjects considered equal but with contradictory desires ? A mixed society exists precisely when a desire (an incommensurable singularity) can be linked to another in a way that does not involve power. A mixed society allows a peaceful interaction between desires. It is therefore not an ideal but a fact, the concrete political fact par excellence - a principle of uncertainty, not a practicality, a tissue, a tension within a given gender. A mixed society does not obey an apportionment logic. Its very structure is what prevents an identity being assigned to an individual.