context: Chances are slight that Brian is white. There is a better than even chance that Jason is tired. We believe that Sandra left the apple. It is likely that if either 'Sandra left the apple' or 'Brian is white' but not both then Emily is a wolf. We believe that if either 'Sandra left the apple' or 'Brian is white' but not both then Julius is a frog. It is improbable that if 'Brian is white and Sandra left the apple' then John moved to the office.
hypothesis: It is improbable that 'Brian is white and Sandra left the apple'.
valid_hypothesis: It is improbable that 'Brian is white and Sandra left the apple'.
invalid_hypothesis: It is probably the case that 'Brian is white and Sandra left the apple'.
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
    0.1::factA.
    0.6::factB.
    0.75::factC.
    %hop1
    0.7::factX:-xor(factC,factA).
    0.75::factY:-xor(factC,factA).
    0.1::factZ:-and(factA,factC).
  
    %hop2
    conclusion:-and(factA,factC).
  
    query(conclusion).
    
hypothesis_assertion: 'Brian is white and Sandra left the apple'.