It is probably not the case that Bernhard is a frog. It is likely that Brian is yellow. Chances are about even that Greg is green. It is likely that if 'Bernhard is a frog' or 'Brian is yellow' or both then Lily is a rhino. We doubt that if 'Bernhard is a frog' or 'Brian is yellow' or both then John took the football. It is unlikely that if 'Brian is yellow and Bernhard is a frog' then Mary went to the kitchen.
There is almost no chance that 'John took the football' or 'Lily is a rhino' or both.
There is a better than even chance that 'John took the football' or 'Lily is a rhino' or both.
There is almost no chance that 'John took the football' or 'Lily 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
  0.25::factA.
  0.7::factB.
  0.5::factC.
  %hop1
  0.7::factX:-or(factA,factB).
  0.2::factY:-or(factA,factB).
  0.2::factZ:-and(factB,factA).

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

  query(conclusion).
  
'John took the football' or 'Lily is a rhino' or both.