There is little chance that Brian is a rhino. We believe that Lily is a swan. It is impossible that Mary left the football. We doubt that if 'Lily is a swan and Brian is a rhino' then Julius is a frog. It is almost certain that if 'Mary left the football and Brian is a rhino' then Fred went to the garden. There is little chance that if either 'Lily is a swan' or 'Mary left the football' but not both then Greg is yellow.
There is a very good chance that 'Lily is a swan' or 'Brian is a rhino' or both.
There is a very good chance that 'Lily is a swan' or 'Brian is a rhino' or both.
It is highly unlikely that 'Lily is a swan' or 'Brian is a rhino' or both.

  and(A,B) :- A,B.
  or(A,B) :- A;B.
  nand(A,B) :- not(and(A,B)).
  nor(A,B) :- not(or(A,B)).
  xor(A,B) :- or(A,B), nand(A,B).

  %hop0
  0.1::factA.
  0.75::factB.
  0.0::factC.
  %hop1
  0.2::factX:-and(factB,factA).
  0.95::factY:-and(factC,factA).
  0.1::factZ:-xor(factB,factC).

  %hop2
  conclusion:-or(factB,factA).

  query(conclusion).
  
'Lily is a swan' or 'Brian is a rhino' or both.