The activity of thinking works with and against the negative. The author examines the paradoxical value of avoiding thoughts in thinking: it is both a protective measure and a harmful solution, in which masochism in its different forms plays a part. The following points are examined: the stimulus barrier function of this dynamic with regard to the threat of a potentially traumatic contact with/between thoughts; the passivity that is expressed by a form of compliant submission to the thought of the other or anxieties of dispossession; the place of the “unconscious sense of guilt” linked to an unpayable debt, which is liable to sterilize the activity of thinking and to produce havoc in the psychic life of a subject who is unable to understand what prevents him/her from living.