context: It is impossible that Gertrude is a cat. It is probably the case that Winona is a wolf. Chances are slight that Greg is a lion. It is impossible that if 'Winona is a wolf' or 'Gertrude is a cat' or both then Lily is green. It is probably the case that if 'Gertrude is a cat' or 'Greg is a lion' or both then Mary got the football. Chances are slight that if 'Greg is a lion and Gertrude is a cat' then Fred went to the garden.
hypothesis: It is likely that 'Winona is a wolf' or 'Fred went to the garden' or both.
valid_hypothesis: It is likely that 'Winona is a wolf' or 'Fred went to the garden' or both.
invalid_hypothesis: There is little chance that 'Winona is a wolf' or 'Fred 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
    0.0::factA.
    0.7::factB.
    0.1::factC.
    %hop1
    0.0::factX:-or(factB,factA).
    0.7::factY:-or(factA,factC).
    0.1::factZ:-and(factC,factA).
  
    %hop2
    conclusion:-or(factB,factZ).
  
    query(conclusion).
    
hypothesis_assertion: 'Winona is a wolf' or 'Fred went to the garden' or both.