1. A rule reasoner comprising: a Rete network builder for receiving an ontology, including an ontology instance represented by a triple and an ontology schema defining classes and properties of the triple, and a reasoning rule, building a Rete network corresponding to the received ontology and the received reasoning rule, selecting a clue pattern corresponding to a wild pattern rule with reference to the ontology schema when a reasoning rule having a wild pattern (the wild pattern rule) is received, rewriting the received wild pattern rule with reference to the selected clue pattern, and adding a test node, an alpha memory node, and a wild rule node so that the rewritten wild pattern rule is incorporated; a Rete network implementer for generating a reasoned triple by implementing the Rete network built by the Rete network builder or generating a reasoning rule into which the wild pattern rule has been dynamically materialized; and a Rete network expander for expanding the Rete network by inputting the new reasoning rule, generated by the Rete network implementer, to the Rete network builder.