It is impossible that Bernhard is a lion. It is probably not the case that John took the apple. We believe that Julius is a rhino. There is a very good chance that if 'Julius is a rhino and Bernhard is a lion' then Emily is a mouse. There is a better than even chance that if 'Bernhard is a lion' or 'Julius is a rhino' or both then Lily is white. It is likely that if 'John took the apple' or 'Bernhard is a lion' or both then Mary left the football.
It is probable that either 'Mary left the football' or 'John took the apple' but not both.
It is highly unlikely that either 'Mary left the football' or 'John took the apple' but not both.
It is probable that either 'Mary left the football' or 'John took the apple' 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
  0.0::factA.
  0.25::factB.
  0.75::factC.
  %hop1
  0.8::factX:-and(factC,factA).
  0.6::factY:-or(factA,factC).
  0.7::factZ:-or(factB,factA).

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

  query(conclusion).
  
Either 'Mary left the football' or 'John took the apple' but not both.