context: It is highly unlikely that Bernhard is a swan. It is highly likely that John picked up the apple. It is probably not the case that Brian is green. It is likely that if 'Brian is green and Bernhard is a swan' then Greg is a lion. It is probable that if 'Brian is green' or 'Bernhard is a swan' or both then Mary got the football. It is highly unlikely that if 'Bernhard is a swan and Brian is green' then Julius is white.
hypothesis: It is highly unlikely that 'Julius is white' or 'Bernhard is a swan' or both.
valid_hypothesis: It is highly unlikely that 'Julius is white' or 'Bernhard is a swan' or both.
invalid_hypothesis: It is probable that 'Julius is white' or 'Bernhard is a swan' 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.
    0.9::factB.
    0.25::factC.
    %hop1
    0.7::factX:-and(factC,factA).
    0.7::factY:-or(factC,factA).
    0.05::factZ:-and(factA,factC).
  
    %hop2
    conclusion:-or(factZ,factA).
  
    query(conclusion).
    
hypothesis_assertion: 'Julius is white' or 'Bernhard is a swan' or both.