It is likely that Lily is a frog. It is impossible that Jason is tired. It is unlikely that Brian is a swan. There is a very good chance that if either 'Jason is tired' or 'Brian is a swan' but not both then Greg is a lion. It is probably the case that if either 'Lily is a frog' or 'Jason is tired' but not both then Bernhard is a lion. It is probably the case that if either 'Lily is a frog' or 'Brian is a swan' but not both then Mary put down the apple.
We doubt that either 'Jason is tired' or 'Greg is a lion' but not both.
We doubt that either 'Jason is tired' or 'Greg is a lion' but not both.
It is likely that either 'Jason is tired' or 'Greg is a lion' but not both.

  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.
  0.0::factB.
  0.2::factC.
  %hop1
  0.8::factX:-xor(factB,factC).
  0.7::factY:-xor(factA,factB).
  0.7::factZ:-xor(factA,factC).

  %hop2
  conclusion:-xor(factB,factX).

  query(conclusion).
  
Either 'Jason is tired' or 'Greg is a lion' but not both.