 Some theorists (e.g. Antony and Levine 1997) have responded by suggesting that, though mental states may be defined in terms of some of their effects, they have other effects that do not follow from those definitions which can figure into causal generalizations that are contingent, informative, and true. For example, even if it follows from a functional definition that pain causes wincing (and thus that the relation between pain and wincing cannot be truly causal), psychologists may discover, say, that pain produces resilience (or submissive behavior) in human beings. One might worry, nonetheless, that functional definitions threaten to leave too many commonly cited generalizations outside the realm of contingency, and thus causal explanation: surely, we may think, we want to affirm claims such as “pain causes wincing”. Such claims could be affirmed, however, if (as seems likely) the most plausible functional theories define sensations such as pain in terms of a small subset of their distinctive psychological, rather than behavioral, effects (see section 4.2).