Full Idea
I take properties and relations to be modal notions. Properties are to be understood in terms of what it would be for them to be exemplified, which means understanding them in terms of a range of possible situations.
Gist of Idea
Properties are modal, involving possible situations where they are exemplified
Source
Robert C. Stalnaker (Mere Possibilities [2012], 1.2)
Book Reference
Stalnaker,Robert C.: 'Mere Possibilities' [Princeton 2012], p.11
A Reaction
I can't make head or tail of a property as anything other than a feature of some entity. Treating properties as a 'range of situations' is just as baffling to me as treating them as sets of objects.
Related Idea
Idea 16437 Possible worlds are properties [Stalnaker]