A Gradable Approach to Dispositions

It has proven difficult to articulate exactly how dispositions are related to subjunctive conditionals. The natural starting-point is a simple conditional analysis, according to which an object o is disposed to give response r to stimulus s if and only if, were o to undergo stimulus s, it would give response r. A glass is disposed to break when dropped, for example, if and only if it would break if dropped. For the moment, at least, we follow David Lewis in assuming that implicit dispositional ascriptions – ‘This glass is fragile’ – can ultimately be understood in terms of explicit correlates – ‘This glass is disposed to break when dropped’.1 This simple analysis is subject to familiar counter-examples involving finks and masks. A disposition is finkish if and only if it would disappear in the presence of the relevant stimulus. Example: a fragile glass is protected by a sorcerer who is prepared, should the glass fall, to cast a spell which will momentarily strengthen the physical structure of the glass, so that it will not break. The glass is disposed to break when dropped, but it will not break if dropped.2 A disposition is masked, in contrast, when it would not disappear in the presence of the relevant stimulus, but where the characteristic manifestation would still be absent. Example: a fragile glass is protected by a sorcerer who is prepared, should the glass fall, to cast a spell which momentarily alters the physical structure of the floor so that the glass will not break.3