context: It is probably not the case that Mary went to the hallway. It is highly unlikely that John took the football. It is likely that Greg is a rhino. There is a very good chance that if 'John took the football' or 'Greg is a rhino' or both then Bernhard is yellow. Chances are about even that if 'Mary went to the hallway and John took the football' then Julius is a frog. There is a very good chance that if either 'John took the football' or 'Greg is a rhino' but not both then Sandra dropped the milk.
hypothesis: It is highly unlikely that 'Bernhard is yellow' or 'Sandra dropped the milk' or both.
valid_hypothesis: It is probably the case that 'Bernhard is yellow' or 'Sandra dropped the milk' or both.
invalid_hypothesis: It is highly unlikely that 'Bernhard is yellow' or 'Sandra dropped the milk' 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.
    0.05::factB.
    0.7::factC.
    %hop1
    0.8::factX:-or(factB,factC).
    0.5::factY:-and(factA,factB).
    0.8::factZ:-xor(factB,factC).
  
    %hop2
    conclusion:-or(factX,factZ).
  
    query(conclusion).
    
hypothesis_assertion: 'Bernhard is yellow' or 'Sandra dropped the milk' or both.