Aliases: [ Stuff type, Stuff types, Types of stuff ]
A collection of collections. Each instance of type of stuff is a collection that is stuff-like in at least one respect. A collection COL is stuff-like just in case there is some sense of 'part' according to which every part of an instance of COL is itself an instance of COL. More precisely, for a collection to be an instance of type of stuff it is sufficient that there be some spec-pred PARTPRED of part (that is, some predicate PARTPRED for which (Genl Preds PARTPRED part) holds), such that if (Isa OBJECT1 COL) and (PARTPRED OBJECT1 OBJECT2), then (Isa OBJECT2 COL). Here are two examples. Consider breathing event. Take an instance of that, say a ten minute long period in which a person is breathing. Imagine some two minute snippet of that, one of its Time Slices (a spec-pred of part). That, too, is an instance of breathing event. So breathing event is a type of stuff, since all Time Slices of an instance of breathing event are also instances of breathing event.
Consider water. Take any instance of water -- say the water in the Pacific Ocean. Now take any portion of that water -- say a handful of it that a person scoops up near Honolulu, one of its physical portion (a spec-pred of part). That handful is itself an instance of water. Hence water is a type of stuff, in virtue of the fact that all physical portion of all instances water are themselves instances of water.
COLis stuff-like just in case there is some sense of 'part' according to which every part of an instance ofCOLis itself an instance ofCOL. More precisely, for a collection to be an instance of type of stuff it is sufficient that there be some spec-predPARTPREDof part (that is, some predicatePARTPREDfor which(Genl Preds PARTPRED part)holds), such that if(Isa OBJECT1 COL)and(PARTPRED OBJECT1 OBJECT2), then(Isa OBJECT2 COL). Here are two examples. Consider breathing event. Take an instance of that, say a ten minute long period in which a person is breathing. Imagine some two minute snippet of that, one of its Time Slices (a spec-pred of part). That, too, is an instance of breathing event. So breathing event is a type of stuff, since all Time Slices of an instance of breathing event are also instances of breathing event.Consider water. Take any instance of water -- say the water in the Pacific Ocean. Now take any portion of that water -- say a handful of it that a person scoops up near Honolulu, one of its physical portion (a spec-pred of part). That handful is itself an instance of water. Hence water is a type of stuff, in virtue of the fact that all physical portion of all instances water are themselves instances of water.
Other examples are: information, which is stuff-like with respect information content; character sequence, which is stuff-like with respect to Sub Character Strings; and list, which is stuff-like with respect to Sub Lists. These examples are somewhat exceptional -- most StuffTypes are like the examples of breathing event and water. See type of object, for the contrasting (but not disjoint) notion of being object-like.