context: It is likely that Greg is a swan. It is probably the case that Daniel left the apple. It is highly likely that Bernhard is a rhino. It is highly likely that if 'Daniel left the apple' or 'Bernhard is a rhino' or both then Julius is a lion. There is a very good chance that if 'Daniel left the apple and Bernhard is a rhino' then John got the milk. It is impossible that if 'Bernhard is a rhino and Daniel left the apple' then Mary went to the garden.
hypothesis: Chances are about even that 'John got the milk and Julius is a lion'.
valid_hypothesis: Chances are about even that 'John got the milk and Julius is a lion'.
invalid_hypothesis: It is impossible that 'John got the milk and Julius is a lion'.
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.
    0.7::factB.
    0.9::factC.
    %hop1
    0.9::factX:-or(factB,factC).
    0.8::factY:-and(factB,factC).
    0.0::factZ:-and(factC,factB).
  
    %hop2
    conclusion:-and(factY,factX).
  
    query(conclusion).
    
hypothesis_assertion: 'John got the milk and Julius is a lion'.