context: It is likely that Jessica is a mouse. There is almost no chance that Mary moved to the garden. It is impossible that Greg is a swan. It is unlikely that if either 'Mary moved to the garden' or 'Jessica is a mouse' but not both then John went to the kitchen. It is impossible that if 'Mary moved to the garden' or 'Jessica is a mouse' or both then Julius is a rhino. It is almost certain that if 'Mary moved to the garden' or 'Greg is a swan' or both then Sandra grabbed the apple.
hypothesis: There is almost no chance that 'Sandra grabbed the apple' or 'Greg is a swan' or both.
valid_hypothesis: There is almost no chance that 'Sandra grabbed the apple' or 'Greg is a swan' or both.
invalid_hypothesis: It is probably the case that 'Sandra grabbed the apple' or 'Greg is a swan' 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
    0.7::factA.
    0.02::factB.
    0.0::factC.
    %hop1
    0.2::factX:-xor(factB,factA).
    0.0::factY:-or(factB,factA).
    0.95::factZ:-or(factB,factC).
  
    %hop2
    conclusion:-or(factZ,factC).
  
    query(conclusion).
    
hypothesis_assertion: 'Sandra grabbed the apple' or 'Greg is a swan' or both.