The Collaborative International Dictionary of English v.0.48:

Dubiosity \Du`bi*os"i*ty\, n.; pl. Dubiosities. [L. dubiosus.]
   The state of being doubtful; a doubtful statement or thing.
   [R.]
   [1913 Webster]

         Men often swallow falsities for truths, dubiosities for
         certainties, possibilities for feasibilities. --Sir T.
                                                  Browne.
   [1913 Webster]