It is probable that Brian is green. Chances are slight that Mary took the football. It is probably the case that John went to the bedroom. Chances are slight that if 'John went to the bedroom' or 'Mary took the football' or both then Julius is yellow. There is little chance that if 'Brian is green' or 'Mary took the football' or both then Gertrude is a mouse. It is almost certain that if 'Mary took the football' or 'John went to the bedroom' or both then Bernhard is a swan.
We believe that 'Brian is green' or 'Mary took the football' or both.
We believe that 'Brian is green' or 'Mary took the football' or both.
We doubt that 'Brian is green' or 'Mary took the football' 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
  0.7::factA.
  0.1::factB.
  0.7::factC.
  %hop1
  0.1::factX:-or(factC,factB).
  0.1::factY:-or(factA,factB).
  0.95::factZ:-or(factB,factC).

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

  query(conclusion).
  
'Brian is green' or 'Mary took the football' or both.