There is little chance that Fred left the football. It is highly unlikely that Julius is white. It is highly likely that Daniel grabbed the milk. It is improbable that if 'Julius is white' or 'Fred left the football' or both then Emily is a cat. It is probably the case that if either 'Fred left the football' or 'Julius is white' but not both then Lily is a lion. Chances are about even that if 'Julius is white and Fred left the football' then Brian is yellow.
Chances are slight that 'Emily is a cat' or 'Fred left the football' or both.
Chances are slight that 'Emily is a cat' or 'Fred left the football' or both.
We believe that 'Emily is a cat' or 'Fred left 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
  0.1::factA.
  0.05::factB.
  0.9::factC.
  %hop1
  0.1::factX:-or(factB,factA).
  0.7::factY:-xor(factA,factB).
  0.5::factZ:-and(factB,factA).

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

  query(conclusion).
  
'Emily is a cat' or 'Fred left the football' or both.