context: It is likely that Lily is a lion. It is almost certain that John took the apple. Chances are about even that Gertrude is a sheep. It is probably the case that if 'Lily is a lion and Gertrude is a sheep' then Julius is white. There is almost no chance that if either 'Gertrude is a sheep' or 'John took the apple' but not both then Jeff moved to the office. We doubt that if 'Lily is a lion' or 'John took the apple' or both then Greg is yellow.
hypothesis: It is almost certain that 'John took the apple' or 'Greg is yellow' or both.
valid_hypothesis: It is almost certain that 'John took the apple' or 'Greg is yellow' or both.
invalid_hypothesis: It is impossible that 'John took the apple' or 'Greg is yellow' 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
    0.7::factA.
    0.95::factB.
    0.5::factC.
    %hop1
    0.7::factX:-and(factA,factC).
    0.02::factY:-xor(factC,factB).
    0.2::factZ:-or(factA,factB).
  
    %hop2
    conclusion:-or(factB,factZ).
  
    query(conclusion).
    
hypothesis_assertion: 'John took the apple' or 'Greg is yellow' or both.