context: It is improbable that Bernhard is white. It is highly likely that Winona is a mouse. It is probably not the case that Brian is yellow. It is likely that if either 'Winona is a mouse' or 'Brian is yellow' but not both then Sandra put down the milk. There is a very good chance that if 'Brian is yellow and Bernhard is white' then Jason is tired. It is likely that if either 'Winona is a mouse' or 'Brian is yellow' but not both then Fred went to the garden.
hypothesis: It is almost certain that either 'Bernhard is white' or 'Fred went to the garden' but not both.
valid_hypothesis: Chances are about even that either 'Bernhard is white' or 'Fred went to the garden' but not both.
invalid_hypothesis: It is almost certain that either 'Bernhard is white' or 'Fred went to the garden' but not 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
    0.1::factA.
    0.9::factB.
    0.25::factC.
    %hop1
    0.7::factX:-xor(factB,factC).
    0.8::factY:-and(factC,factA).
    0.7::factZ:-xor(factB,factC).
  
    %hop2
    conclusion:-xor(factA,factZ).
  
    query(conclusion).
    
hypothesis_assertion: Either 'Bernhard is white' or 'Fred went to the garden' but not both.