context: It is unlikely that Sandra left the milk. It is impossible that Jessica is a cat. We believe that Greg is a lion. There is almost no chance that if either 'Sandra left the milk' or 'Jessica is a cat' but not both then Emily is a sheep. It is probably not the case that if 'Sandra left the milk and Greg is a lion' then Mary got the football. Chances are about even that if 'Jessica is a cat' or 'Greg is a lion' or both then John went to the garden.
hypothesis: It is probable that 'Jessica is a cat' or 'Mary got the football' or both.
valid_hypothesis: It is highly unlikely that 'Jessica is a cat' or 'Mary got the football' or both.
invalid_hypothesis: It is probable that 'Jessica is a cat' or 'Mary got the football' or both.
problog: 
    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.
    0.0::factB.
    0.75::factC.
    %hop1
    0.02::factX:-xor(factA,factB).
    0.25::factY:-and(factA,factC).
    0.5::factZ:-or(factB,factC).
  
    %hop2
    conclusion:-or(factB,factY).
  
    query(conclusion).
    
hypothesis_assertion: 'Jessica is a cat' or 'Mary got the football' or both.