The paper addresses the psychoanalytic question of how the child comes to know reality, especially a reality which demands two-tracked thinking. Some contradictions in Bion's theories of thinking are observed. Where there is a real difficulty or deficit in making links, rather than an attack on a previously established link, the therapist may need to attend to certain temporal and dynamic features of the link which can enable sequentiality, ordinality and twoness to be bearable and pleasurable. Clinical material from autistic and psychotic patients with thinking disorders is discussed, and some parallels between play and syntax are suggested.