an·tin·o·my 
(ăn-tĭnə-mē)
(ăn-tĭnə-mē)n. pl. an·tin·o·mies
1. Contradiction or opposition, especially between two laws or rules.
2. A contradiction between principles or conclusions that seem equally necessary and reasonable; a paradox.
[Latin antinomia, from Greek antinomiā : anti-, anti- + nomos, law; see nem- in the Appendix of Indo-European roots.]
an′ti·nomic (ăn′tĭ-nŏmĭk) adj.