context: Chances are about even that Gertrude is a cat. There is almost no chance that Mary left the milk. It is highly unlikely that Brian is a lion. There is little chance that if either 'Brian is a lion' or 'Gertrude is a cat' but not both then John dropped the apple. It is almost certain that if either 'Mary left the milk' or 'Gertrude is a cat' but not both then Bill went to the garden. Chances are slight that if either 'Mary left the milk' or 'Gertrude is a cat' but not both then Emily is a mouse.
hypothesis: There is almost no chance that 'Emily is a mouse' or 'Bill went to the garden' or both.
valid_hypothesis: Chances are about even that 'Emily is a mouse' or 'Bill went to the garden' or both.
invalid_hypothesis: There is almost no chance that 'Emily is a mouse' or 'Bill went to the garden' 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
    0.5::factA.
    0.02::factB.
    0.05::factC.
    %hop1
    0.1::factX:-xor(factC,factA).
    0.95::factY:-xor(factB,factA).
    0.1::factZ:-xor(factB,factA).
  
    %hop2
    conclusion:-or(factZ,factY).
  
    query(conclusion).
    
hypothesis_assertion: 'Emily is a mouse' or 'Bill went to the garden' or both.