This is an open access title available under the terms of a CC BY-NC-ND 4.0 International licence. It is free to read at Oxford Scholarship Online and offered as a free PDF download from OUP and selected open access locations. Personal autonomy is often lauded as a key value in contemporary Western bioethics. Though the claim that there is an important relationship between autonomy and rationality is often treated as uncontroversial in this...