Adjuncts appear to be partial participants for certain grammatical processes, for instance: they may be targets for dependent case assignment when c-commanded by another nominal, but do not themselves trigger dependent case assignment to a lower nominal. This talk develops a theory of partial participation for adjuncts couched in a path-based theory of locality like that developed in Sunderesan et al. 2019, where sets of selection relationships between clausal elements determines whether or not they are local to each other. Patterns of partial participation arise as a result of differences in selectional relationships between arguments and adjuncts.