# What is property?

Suppose , I have two objects A and B. A has a set of properties P and B has a set of properties Q. It is possible that when I combine A and B the combination has a property c that is neither in P nor in Q (i.e c ∉ P∪Q ). Examples are everywhere so i am not feeling the need to provide any. Now my question is : what exactly is property and where do new properties come from?

• See Properties: "Properties (also called ‘attributes,’ ‘qualities,’ ‘features,’ ‘characteristics,’ ‘types’) are those entities that can be predicated of things or, in other words, attributed to them. Moreover, properties are entities that things are said to bear, possess or exemplify." Commented Jan 25, 2018 at 11:46
• pvspade.com/Logic/index.html You might also be interested in Prof. Spades "Warp and Woof of Metaphysics" Commented Jan 25, 2018 at 15:17
• (On the above page, Things to download, Medieval Philosophy, then you will see this PDF.) Commented Jan 25, 2018 at 15:20
• Are you interested in a philosophical notion (which is loose and vague as actually used) or some precise formalization? In formal theories properties are identified with one-place predicates. Predicates (not necessarily one-place) are built from some pre-specified basic predicates by using logical connectives and quantifiers. What you mean by "combining" objects is unclear, why should we expect that the "combination" would even have the properties of the originals? Say, green and red objects are both mono-color, but their combination isn't. Commented Jan 25, 2018 at 21:36
• Hydrogen's not wet and oxygen's not wet but water is wet. Is that an example of what you mean? Surely the whole often has properties not possessed by any of the parts. A semicircle isn't round but if you put two of them together it's a circle, which is round. This by the way is why the concept of "emergence" is murky and explains far less than its proponents think it does. Commented Jan 25, 2018 at 23:36