context: It is improbable that John went to the kitchen. It is probable that Greg is a rhino. There is a very good chance that Mary left the football. There is a very good chance that if 'John went to the kitchen' or 'Greg is a rhino' or both then Emily is a wolf. There is almost no chance that if either 'John went to the kitchen' or 'Mary left the football' but not both then Lily is a lion. It is probably not the case that if 'John went to the kitchen and Mary left the football' then Julius is a swan.
hypothesis: It is probable that 'Julius is a swan' or 'Lily is a lion' or both.
valid_hypothesis: There is almost no chance that 'Julius is a swan' or 'Lily is a lion' or both.
invalid_hypothesis: It is probable that 'Julius is a swan' or 'Lily is a lion' 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
    0.1::factA.
    0.7::factB.
    0.8::factC.
    %hop1
    0.8::factX:-or(factA,factB).
    0.02::factY:-xor(factA,factC).
    0.25::factZ:-and(factA,factC).
  
    %hop2
    conclusion:-or(factZ,factY).
  
    query(conclusion).
    
hypothesis_assertion: 'Julius is a swan' or 'Lily is a lion' or both.