We believe that Mary got the football. It is impossible that Jessica is a cat. It is impossible that John discarded the apple. It is probably not the case that if 'Jessica is a cat' or 'John discarded the apple' or both then Jason is tired. It is certain that if either 'John discarded the apple' or 'Mary got the football' but not both then Bernhard is a frog. It is almost certain that if 'John discarded the apple' or 'Mary got the football' or both then Brian is a rhino.
We believe that 'Mary got the football' or 'Jessica is a cat' or both.
We believe that 'Mary got the football' or 'Jessica is a cat' or both.
It is improbable that 'Mary got the football' or 'Jessica is a cat' 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
  0.75::factA.
  0.0::factB.
  0.0::factC.
  %hop1
  0.25::factX:-or(factB,factC).
  1.0::factY:-xor(factC,factA).
  0.95::factZ:-or(factC,factA).

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

  query(conclusion).
  
'Mary got the football' or 'Jessica is a cat' or both.