This paper considers how cognitive architecture impacts and constrains the rational requirement to respond to reasons. Informational encapsulation and its close relative belief fragmentation can render an agent’s own reasons inaccessible to her, thus preventing her from responding to them. For example, someone experiencing imposter phenomenon might be well aware of their own accomplishments in certain contexts but unable to respond to those reasons when forming beliefs about their own self-worth. In such cases, are our beliefs irrational for failing to (...) respond to our own reasons? Or are they excused on grounds of the reasons’ inaccessibility? I argue that in such cases, the rational status of the belief that fails to respond to reasons is modulated by the degree of encapsulation of the system that produces it. Yet because our cognitive systems are rarely perfectly encapsulated, our failures to respond to reasons are almost always irrational to some degree. (shrink)