context: It is highly unlikely that John went to the bedroom. It is impossible that Sandra took the milk. It is almost certain that Brian is a lion. There is a very good chance that if 'John went to the bedroom' or 'Brian is a lion' or both then Jason is tired. It is probable that if 'Sandra took the milk and John went to the bedroom' then Bernhard is a frog. It is probable that if 'Brian is a lion' or 'John went to the bedroom' or both then Lily is yellow.
hypothesis: We believe that 'Sandra took the milk' or 'Jason is tired' or both.
valid_hypothesis: We believe that 'Sandra took the milk' or 'Jason is tired' or both.
invalid_hypothesis: Chances are slight that 'Sandra took the milk' or 'Jason is tired' 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
    0.05::factA.
    0.0::factB.
    0.95::factC.
    %hop1
    0.8::factX:-or(factA,factC).
    0.7::factY:-and(factB,factA).
    0.7::factZ:-or(factC,factA).
  
    %hop2
    conclusion:-or(factB,factX).
  
    query(conclusion).
    
hypothesis_assertion: 'Sandra took the milk' or 'Jason is tired' or both.