Full Idea
Dispositionality can be understood as a sort of selection function - a natural one in this case - and picks out a limited number of outcomes from all the ones that the disposition is for.
Gist of Idea
Dispositionality is a natural selection function, picking outcomes from the range of possibilities
Source
S.Mumford/R.Lill Anjum (Getting Causes from Powers [2011], 8.9)
Book Reference
Anjum,R.J./Mumford,S.: 'Getting Causes from Powers' [OUP 2011], p.189
A Reaction
Functions should strictly have one output. This sounds wrong. The disposition pushes its powers into the environment, but it is the surrounding contextual powers which do the selecting, in concert. No disposition does any selecting