As for Avicenna the human soul is a complete substance which does not inhere in the body nor is imprinted in it, asserting its survival after the death of the body seems easy. Yet, he needs the body to explain its individuation. The paper analyzes Avicenna's arguments in the De anima sections, V, 3 & 4, of the Shifā' in order to explore the exact causal relation there is between the human soul and its body and confronts these arguments with relevant passages in the Metaphysics. It argues that the causal relation between body and soul remains obscure and that, though Avicenna claims that there is a personal immortality and that the disembodied soul remains individuated, he does not provide a satisfactory ontological account for it.