ABSTRACT
Our view of adolescence today has changed. The individual's history and background are still the determining factors, as illustrated by the model of Nachträglichkeit 2 . However, the clinical experience of the last few decades, together with new ideas on causality, casts doubt on the old strictly deterministic approach. That conception has now expanded into a probabilistic vision in which a margin of indeterminacy always persists, in particular in far-from-equilibrium problem situations, 150so that much greater importance is attached to the random and to the effect of current events. It is therefore appropriate for us to think of psychic functioning in terms not only of its predeterminations and structural constraints, but also of the unforeseen contributions—the noise—of internal and external excitations. These are constantly modifying, calling into question, or conversely fixing and consolidating the psyche's productions and acts through the dialectic of permanence and change, through the possibility of bifurcations and transformations or, conversely, of infinite repetition of the same. Admittedly, the initially infinite and unpredictable virtualities are gradually reduced as the psyche becomes more structured, giving way to increasingly organized forms. But there remains even then a space open to interrogation, to the calling into question of the familiar and the already known, and hence to the possibility of transformation and self-creation. In adolescence, the equilibrium between the two poles of "inside" and "outside" is particularly unstable owing to the imperatives of the pleasure— unpleasure principle. This means that aspirations concerning the object, whether nostalgic or new, may either be kept available or, instead, be excluded; that identity may be confronted, enriched or, alternatively, called into question; and, more generally, that the preconscious and conscious space may be used to the full or, conversely, disabled to a greater or lesser extent (Cahn, 1996).
