Explain why the three sub-types of thought alienation — insertion, withdrawal, and broadcasting — are described as varying by the 'direction' of the felt interference.

All three sub-types share the same underlying disturbance: the ordinarily invisible boundary that keeps a person's thoughts private and self-generated has broken down. What differs between them is simply which way the traffic across that boundary is felt to run. In insertion, something crosses in — a foreign thought enters the mind from outside. In withdrawal, something crosses out — the person's own thought is taken away from them. In broadcasting, the boundary itself becomes leaky in a different sense — the person's thoughts remain their own, but are no longer confined to them, becoming accessible to others. Thinking of the three as one disturbance viewed from three different directions, rather than as three unrelated symptoms, is what makes their shared underlying logic, and their shared clinical significance, clear.