context: It is highly unlikely that Lily is a rhino. It is highly unlikely that Brian is a lion. There is a very good chance that Greg is white. It is unlikely that if 'Greg is white and Brian is a lion' then Julius is a swan. It is probably the case that if 'Greg is white' or 'Lily is a rhino' or both then Mary went to the bedroom. It is probably not the case that if either 'Lily is a rhino' or 'Greg is white' but not both then Bernhard is a rhino.
hypothesis: There is a very good chance that 'Brian is a lion' or 'Bernhard is a rhino' or both.
valid_hypothesis: It is probably not the case that 'Brian is a lion' or 'Bernhard is a rhino' or both.
invalid_hypothesis: There is a very good chance that 'Brian is a lion' or 'Bernhard is a rhino' 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.
    0.05::factB.
    0.8::factC.
    %hop1
    0.2::factX:-and(factC,factB).
    0.7::factY:-or(factC,factA).
    0.25::factZ:-xor(factA,factC).
  
    %hop2
    conclusion:-or(factB,factZ).
  
    query(conclusion).
    
hypothesis_assertion: 'Brian is a lion' or 'Bernhard is a rhino' or both.