SummaryStarting with an analysis of the respiratory function and of the way it automatically connects the living organism with the physical milieu without any conscious or voluntary effort, Dr De Greeff then asserts that, on the Psychological level, similar basic mechanisms connect the individual with the social environment, and more generally with the Cosmos.Typical disorders of these mechanisms are to be seen in melancholic depressions and in the feelings of strangeness and loneliness they bring about. These mechanisms have à neural basis in the diencephalic region and may be influenced by shock therapies. On the other hand, cerebral surgery shows that the frontal lobe intervenes to adjust these connecting mechanisms to the external world in its concrete structure, present and future.The author then criticizes the freudian conception, as he understands it, and proposes to substitute to theInstinct‐Realitydichotomy the antagonism of two internal attitudes, which are basic, automatic, and nearly organic, in the sense defined above: thesympathy‐attitude, which results in valorisation of and subordination to the object, and thedefence‐attitude, which manifests itself in aggression and aims at annihilating the object. These attitudes are complementary and any awakening of one of them supposes the inhibition of the other one. But such an inhibition never reaches the stage of an absolute suppression.So much for the instinctive, unconscious and diencephalic basis of action. What kind of new developments do the cerebral cortex and the higher mental functions bring about? They make the individual aware of his basic attitudes, or, more exactly, of the way the object is affected by them so as to appear pleasant or unpleasant, lovable or threatening. They give him the possibility of accepting or refusing the first movements of instinct, and of stabilizing, delaying or inhibiting the corresponding reactions. They are the basis of temporal dimension and integration, of choice, liberty and mo