Not being able to equilibrate affirmations and negations, the schizophrenic patient accedes only exceptionally to the majoring equilibrations of the second and third levels. In the logico-mathematic field, he does not approach the constructive synthetizing generalisations of reasoning. Lacking reflective abstraction, he cannot balance his logico-mathematic reasoning and differentiate what is structurally possible from what is materially possible, thus explaining his inaccessibility to perceive logic necessities, contrasting with the certainties of his delirium. In the logico-experimental domain, he reaches only rarely clause reasoning generalisation, and relapses regularly to the level of inappropriate generalisations of the extended inductive type. It is useless to try to find the "primum movens" of his difficulties, either in his imbalance assimilation/accommodation, or in his impossibility to see his contradictions, or even in his incapacity to equilibrate affirmations and negations. The majoring equilibrations, of which he is unable, are the functional expression of structures which do not follow the linear causality of Laplace's determinism but the circular causality characteristic of teleonomic processes. After a month of neuroleptic treatment, the decompensated schizophrenic's balance between assimilation and accommodation is partially restored.