Insufficient True Antecedents and Heim Sequences

This paper aims to unify two puzzles. One is the puzzle of Heim sequences: while many Sobel sequences can be felicitously uttered, their reverses, i.e. Heim sequences, often sound bad. The other puzzle is that true-true counterfactuals, i.e. counterfactuals with both true antecedents and true consequents, are invariably true on the standard Stalnaker-Lewis semantics, while some of them appear to be infelicitous to utter. True-true counterfactuals are first divided into two categories, which I call “unconnected” and “insufficient” true-trues. The two kinds, I argue, deserve distinct pragmatic accounts. Then, it is argued that the category of insufficient true-trues is a special case of Heim sequences, in the sense that whatever is responsible for the infelicity of Heim sequences should also account for the infelicity of insufficient true-trues. Evidence for this unification is that the (in)felicity of both insufficient true-trues and Heim sequences reacts in similar ways to a series of contextual variations. Given the unification, I review two existing pragmatic accounts of Heim sequences—Moss in Nouˆs 46:561–586, 2012 and Ippolito in Ling & Phil 43:633–671, 2020—and try to apply them to insufficient true-trues. As will be clear, both accounts solve the insufficient true-true puzzles to the same degree of success as they solve the puzzle of Heim sequences, and neither account is completely satisfactory. In comparison, Ippolito’s account is more promising, and I provide a modification of it, which is expected to be an improved solution to both puzzles.