context: It is improbable that John discarded the apple. There is a better than even chance that Lily is a rhino. It is likely that Greg is a swan. We doubt that if 'Greg is a swan' or 'Lily is a rhino' or both then Brian is a frog. There is almost no chance that if either 'Lily is a rhino' or 'Greg is a swan' but not both then Mary went to the kitchen. It is impossible that if 'Greg is a swan' or 'Lily is a rhino' or both then Julius is yellow.
hypothesis: It is likely that 'Mary went to the kitchen' or 'Greg is a swan' or both.
valid_hypothesis: It is likely that 'Mary went to the kitchen' or 'Greg is a swan' or both.
invalid_hypothesis: It is improbable that 'Mary went to the kitchen' 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
    0.1::factA.
    0.6::factB.
    0.7::factC.
    %hop1
    0.2::factX:-or(factC,factB).
    0.02::factY:-xor(factB,factC).
    0.0::factZ:-or(factC,factB).
  
    %hop2
    conclusion:-or(factY,factC).
  
    query(conclusion).
    
hypothesis_assertion: 'Mary went to the kitchen' or 'Greg is a swan' or both.