context: It is highly likely that Mary grabbed the apple. It is likely that Emily is a mouse. There is little chance that Julius is a lion. Chances are about even that if 'Emily is a mouse and Julius is a lion' then Daniel got the football. It is probably not the case that if either 'Julius is a lion' or 'Emily is a mouse' but not both then Lily is a frog. There is a better than even chance that if 'Julius is a lion' or 'Mary grabbed the apple' or both then John moved to the garden.
hypothesis: It is probably not the case that either 'Mary grabbed the apple' or 'John moved to the garden' but not both.
valid_hypothesis: It is probably not the case that either 'Mary grabbed the apple' or 'John moved to the garden' but not both.
invalid_hypothesis: It is almost certain that either 'Mary grabbed the apple' or 'John moved 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
    0.9::factA.
    0.7::factB.
    0.1::factC.
    %hop1
    0.5::factX:-and(factB,factC).
    0.25::factY:-xor(factC,factB).
    0.6::factZ:-or(factC,factA).
  
    %hop2
    conclusion:-xor(factA,factZ).
  
    query(conclusion).
    
hypothesis_assertion: Either 'Mary grabbed the apple' or 'John moved to the garden' but not both.