It is certain that Lily is a frog. It is probably not the case that Mary got the football. There is little chance that Bernhard is a rhino. It is improbable that if either 'Bernhard is a rhino' or 'Mary got the football' but not both then Gertrude is a mouse. It is probably not the case that if either 'Mary got the football' or 'Bernhard is a rhino' but not both then Julius is green. It is impossible that if 'Mary got the football and Bernhard is a rhino' then John went to the hallway.
We doubt that 'John went to the hallway' or 'Lily is a frog' or both.
It is certain that 'John went to the hallway' or 'Lily is a frog' or both.
We doubt that 'John went to the hallway' or 'Lily is a frog' 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
  1.0::factA.
  0.25::factB.
  0.1::factC.
  %hop1
  0.1::factX:-xor(factC,factB).
  0.25::factY:-xor(factB,factC).
  0.0::factZ:-and(factB,factC).

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

  query(conclusion).
  
'John went to the hallway' or 'Lily is a frog' or both.