Stephen Finlay analyses ‘ought’ in terms of probability. According to him, normative ‘ought's are statements about the likelihood that an act will realize some (contextually supplied) end. I raise a problem for this theory. It concerns the relation between ‘ought’ and the balance of reasons. ‘A ought to Φ’ seems to entail that the balance of reasons favours that A Φ-es, and vice versa. Given Finlay's semantics for ‘ought’, it also makes sense to think of reasons and their weight in terms of probability. In this paper, I develop such a theory of weight. It turns out, however, that it cannot explain the entailments. This leaves Finlay with a challenge: to explain these entailments in some other way consistent with his theory, or to show why the appearances deceive and there are no such entailments.