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The psycho-analytic picture as illuminated by her work emphasizes two principal stages of normal development, which Melanie Klein called "positions". The first, issuing from the infant's unintegrated and violently conflicting attitude to the vital objects of this world, is marked by a persecutory anxiety which may retard or disrupt the integration of the infant's ego. In the second stage the infant begins to apprehend that the gratifying objects he needs and loves are but other aspects of the menacing and frustrating objects he hates. This discovery arouses concern for these objects, and he experiences depression. However, in so far as he can tolerate the depressive position, it gives rise to reparative impulses and a capacity for unselfish concern and protective love. The extent to which he achieves this normal outcome determines the stability of his health or his liability to illness. In Melanie Klein's view, two of Freud's great discoveries, the super-ego and the Oedipus complex, have their roots in these early periods of development.