How is the range of an rdf:object specified in rdfs ?

From: Seth Russell <seth@robustai.net> Date: Wed, 06 Dec 2000 13:31:55 -0800 Message-ID: <3A2EB04B.90289ACB@robustai.net> To: RDF-IG <www-rdf-interest@w3.org> · This archive was generated by hypermail 2.4.0 : Friday, 17 January 2020 22:44:27 UTC

The  [RDF Schema] has the following description of the
rdf:object property of the reification quad:

<rdf:Property
about="http://www.w3.org/1999/02/22-rdf-syntax-ns#object">
  <rdfs:label xml:lang="en">object</rdfs:label>
  <rdfs:label xml:lang="fr">objet</rdfs:label>
  <rdfs:domain
rdf:resource="http://www.w3.org/1999/02/22-rdf-syntax-ns#Statement"/>

</rdf:Property>

Why doesn't this this description show that the range of the
object must be a resource or a literal?
What am i missing here?

[RDF Schema] http://www.w3.org/2000/01/rdf-schema

Seth Russell