subject=predicate ?

Hello all,
 
is this a valid RDF:

<rdfs:Property ID="aProperty">
    <rdf:comment>This is a somewhat important property.</rdf:comment>
    <aProperty rdf:resource="http://resource"/>
</rdfs:Property>

where default namespace is this document.
Some examples out of the blue:

usefulness of being useful
sense of having sense
importance of being important 
smartness of being smart
thoughtfulness of being thoughtful
existence of existence
etc.

This is a pessimistic one :-)
<rdf:Property ID="sense">
    <rdf:comment>A measure of making sense on the scale 1 to 100.</rdf:comment>
    <sense>5</sense>
</rdf:Property>
 
And here is another one. Russian writer M. Gorkiy in a play "On the bottom"
has this idea that being kind is not kind at all.
Could this be modeled:

<rdfs:Property ID="kindness">
    <kindness>0</kindness>
</rdfs:Property>

I guess the proper way to formulate the question is:
is it valid from RDF standpoint (an why not?) 
if subject and predicate are same?

Object and subject can obviously be same:
My advisor is myself, for example.

All three are the same:
vagueness of being vague is vague

Thanks,

--Nikita.