It is unlikely that Julius is a lion. It is unlikely that Mary went to the hallway. There is a very good chance that Bernhard is a rhino. It is probably the case that if 'Bernhard is a rhino' or 'Julius is a lion' or both then Greg is green. It is highly likely that if 'Mary went to the hallway' or 'Julius is a lion' or both then John took the football. Chances are slight that if either 'Bernhard is a rhino' or 'Mary went to the hallway' but not both then Brian is a swan.
It is probably not the case that 'Mary went to the hallway' or 'Julius is a lion' or both.
It is probably not the case that 'Mary went to the hallway' or 'Julius is a lion' or both.
It is likely that 'Mary went to the hallway' or 'Julius is a lion' 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
  0.2::factA.
  0.2::factB.
  0.8::factC.
  %hop1
  0.7::factX:-or(factC,factA).
  0.9::factY:-or(factB,factA).
  0.1::factZ:-xor(factC,factB).

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

  query(conclusion).
  
'Mary went to the hallway' or 'Julius is a lion' or both.