On Wed, May 28, 2014 at 10:37 AM, Daniel Kinzler <daniel.kinzler@wikimedia.de> wrote:

More fundamentally, they are semantically different: an item describes a concept
in "the real world", while a property is a structural component used for such a
description.

As I perceive it, a property is a normal item (concept) imbued with the option to use it as predicate and allow it to use different datatypes.

There is no property that cannot be expressed as an item, even properties that represent an identifier, they also could be said that they are a concept in the real world.

I understand that from the software side you need to make a difference between "basic concepts" (items) and "concepts that can be used as predicates" (properties). From the community side we also need to scrutinize and "rinse" the concepts that hide behind the words before using them as predicates, but sometimes it is good to stop and consider what are we really doing.

Yes, properies are simmilar to data items, and in some cases, there may be an
item representing the same concept that is represented by a property entity.

I haven't found yet a property that couldn't be expressed as an item.

I don't see why that is a problem, while I can see a lot of confusion arising from
mixing them.

It is not a problem now but I considered interesting to analyze what is the substance of the distinction. If properties and concepts are separate in the end we will be reproducing their ontological structure when organizing them. So then it might not make sense to use "subproperty of" to organize properties, but just "corresponds to item".

Gerard, thanks for bringing the example of OmegaWiki, it is interesting that two independent communities came to the same thoughts without any contact between them :)

Cheers,

Micru