It is likely that John took the apple. There is a very good chance that Greg is a swan. It is probable that Winona is a mouse. There is little chance that if 'Greg is a swan' or 'John took the apple' or both then Jason is tired. There is little chance that if 'Greg is a swan and Winona is a mouse' then Antoine is hungry. Chances are about even that if either 'John took the apple' or 'Greg is a swan' but not both then Bernhard is green.
It is likely that either 'Jason is tired' or 'Winona is a mouse' but not both.
It is likely that either 'Jason is tired' or 'Winona is a mouse' but not both.
There is almost no chance that either 'Jason is tired' or 'Winona is a mouse' 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.
  0.8::factB.
  0.7::factC.
  %hop1
  0.1::factX:-or(factB,factA).
  0.1::factY:-and(factB,factC).
  0.5::factZ:-xor(factA,factB).

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

  query(conclusion).
  
Either 'Jason is tired' or 'Winona is a mouse' but not both.