This paper reappraises the view of John McPeck that critical thinking can only be taught within rather than across the disciplines. In particular the paper explores one aspect of McPeck's position: his resistance to teaching informal logic as a means of teaching critical thinking. The paper draws upon the author's experience of teaching critical thinking in the USA, Britain and Australia to outline some of the challenges and issues arising in devising and teaching courses in reasoning and informal logic and seeks to show that McPeck's misgivings are not entirely well-founded. (Contains 2 notes.)