context: It is highly likely that Bernhard is a frog. It is likely that Winona is a cat. It is likely that John moved to the office. There is a better than even chance that if 'Bernhard is a frog' or 'John moved to the office' or both then Sandra took the apple. It is improbable that if 'Bernhard is a frog' or 'Winona is a cat' or both then Lily is a frog. We doubt that if either 'Winona is a cat' or 'Bernhard is a frog' but not both then Brian is a lion.
hypothesis: We believe that 'John moved to the office' or 'Lily is a frog' or both.
valid_hypothesis: We believe that 'John moved to the office' or 'Lily is a frog' or both.
invalid_hypothesis: It is unlikely that 'John moved to the office' or 'Lily is a frog' 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
    0.9::factA.
    0.7::factB.
    0.7::factC.
    %hop1
    0.6::factX:-or(factA,factC).
    0.1::factY:-or(factA,factB).
    0.2::factZ:-xor(factB,factA).
  
    %hop2
    conclusion:-or(factC,factY).
  
    query(conclusion).
    
hypothesis_assertion: 'John moved to the office' or 'Lily is a frog' or both.