context: It is highly unlikely that Sandra grabbed the milk. It is probably not the case that Mary picked up the apple. We doubt that John moved to the office. Chances are about even that if 'John moved to the office and Sandra grabbed the milk' then Jessica is a cat. There is almost no chance that if 'Mary picked up the apple and John moved to the office' then Greg is a rhino. It is almost certain that if either 'John moved to the office' or 'Sandra grabbed the milk' but not both then Julius is white.
hypothesis: It is impossible that 'John moved to the office and Jessica is a cat'.
valid_hypothesis: It is impossible that 'John moved to the office and Jessica is a cat'.
invalid_hypothesis: It is probable that 'John moved to the office and Jessica is a cat'.
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.
    0.25::factB.
    0.2::factC.
    %hop1
    0.5::factX:-and(factC,factA).
    0.02::factY:-and(factB,factC).
    0.95::factZ:-xor(factC,factA).
  
    %hop2
    conclusion:-and(factC,factX).
  
    query(conclusion).
    
hypothesis_assertion: 'John moved to the office and Jessica is a cat'.