Bion's work on the genesis, agenesis and dysgenesis of thought, and its subsequent development, allows us to delineate two fundamental mechanisms which are used to avoid the painful anxieties associated with the birth of a thought. These anxieties, which are perhaps best covered by the term catastrophic anxiety, may be avoided by evacuation of the elements that thought is born from, or by the conversion of these elements into pseudo-elements or lies. The clinical concept of alexithymia, which evolved from work with psychosomatic patients, illustrates how these mechanisms may be manifested clinically by disordered thought and psychosomatic illness.