Diminished rationality and the space of reasons

Some theories of language, thought, and experience require their adherents to say unpalatable things about human individuals whose capacities for rational activity are seriously diminished. Donald Davidson, for example, takes the interdependence of the concepts of thought and language to entail that thoughts may only be attributed to an individual who is an interpreter of others’ speech. And John McDowell's account of human experience as the involuntary exercise of conceptual capacities can be applied easily only to individuals who make some reasonable judgments, because conceptual capacities are paradigmatically exercised in judgments. In both cases, we seem forced towards an error theory about any ordinary understanding of impaired human individuals as minded, or as undergoing human experience.