context: It is probable that Lily is a rhino. There is a very good chance that Yann is tired. Chances are about even that Emily is a mouse. Chances are slight that if 'Yann is tired and Emily is a mouse' then Daniel put down the milk. It is improbable that if either 'Lily is a rhino' or 'Emily is a mouse' but not both then Brian is a lion. There is a very good chance that if either 'Yann is tired' or 'Lily is a rhino' but not both then John went to the garden.
hypothesis: It is highly likely that either 'John went to the garden' or 'Daniel put down the milk' but not both.
valid_hypothesis: It is probably not the case that either 'John went to the garden' or 'Daniel put down the milk' but not both.
invalid_hypothesis: It is highly likely that either 'John went to the garden' or 'Daniel put down the milk' 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
    0.7::factA.
    0.8::factB.
    0.5::factC.
    %hop1
    0.1::factX:-and(factB,factC).
    0.1::factY:-xor(factA,factC).
    0.8::factZ:-xor(factB,factA).
  
    %hop2
    conclusion:-xor(factZ,factX).
  
    query(conclusion).
    
hypothesis_assertion: Either 'John went to the garden' or 'Daniel put down the milk' but not both.