context: It is likely that John got the apple. It is probably the case that Bernhard is green. It is highly unlikely that Gertrude is a mouse. It is impossible that if 'Bernhard is green and John got the apple' then Antoine is thirsty. We doubt that if 'Gertrude is a mouse' or 'Bernhard is green' or both then Mary left the football. There is a very good chance that if 'John got the apple and Bernhard is green' then Greg is a rhino.
hypothesis: Chances are about even that 'Antoine is thirsty' or 'Greg is a rhino' or both.
valid_hypothesis: Chances are about even that 'Antoine is thirsty' or 'Greg is a rhino' or both.
invalid_hypothesis: It is impossible that 'Antoine is thirsty' or 'Greg 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
    0.7::factA.
    0.7::factB.
    0.05::factC.
    %hop1
    0.0::factX:-and(factB,factA).
    0.2::factY:-or(factC,factB).
    0.8::factZ:-and(factA,factB).
  
    %hop2
    conclusion:-or(factX,factZ).
  
    query(conclusion).
    
hypothesis_assertion: 'Antoine is thirsty' or 'Greg is a rhino' or both.