Levels of performance in typical Jamaican schools constitute a chronic problem. Although one can point to cases of excellent achievement throughout the system, from all-age schools to traditional high schools, the dominant impression is of poor performance on almost all standard indicators: Cambridge General Certificate of Education A Level or Caribbean Examinations Council performance at one end, levels of literacy at the other. While overcrowding and underfunding are equally obvious, one major contributory factor is the achievement level of typical teachers. Teachers who believe themselves to be using standard English are oblivious of the nonstandard forms they use. Many teachers on the recent upgrading programme are still unable to pass an examination based on the content of the primary school mathematics curriculum. No doubt analogous inadequacies regarding the content of the curriculum could be uncovered in subjects thought less central than English and mathematics. This paper, however, looks at an area of cognitive skill that is paradoxically central to most subjects but universally ignored in their teaching and in the preparation of teachers to teach them (see Brandon 1985): elementary deductive logic.