context: It is probably not the case that Julius is a swan. It is highly likely that Emily is a mouse. There is almost no chance that Lily is green. We doubt that if 'Julius is a swan' or 'Emily is a mouse' or both then Brian is a frog. There is a very good chance that if 'Julius is a swan' or 'Emily is a mouse' or both then Mary went to the bedroom. There is a better than even chance that if 'Emily is a mouse' or 'Julius is a swan' or both then Gertrude is a sheep.
hypothesis: It is highly likely that 'Gertrude is a sheep' or 'Emily is a mouse' or both.
valid_hypothesis: It is highly likely that 'Gertrude is a sheep' or 'Emily is a mouse' or both.
invalid_hypothesis: We doubt that 'Gertrude is a sheep' or 'Emily is a mouse' 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
    0.25::factA.
    0.9::factB.
    0.02::factC.
    %hop1
    0.2::factX:-or(factA,factB).
    0.8::factY:-or(factA,factB).
    0.6::factZ:-or(factB,factA).
  
    %hop2
    conclusion:-or(factZ,factB).
  
    query(conclusion).
    
hypothesis_assertion: 'Gertrude is a sheep' or 'Emily is a mouse' or both.