It is unlikely that Greg is gray. It is likely that Yann is hungry. There is a very good chance that Antoine is bored. We doubt that if either 'Greg is gray' or 'Yann is hungry' but not both then John went to the garden. It is almost certain that if either 'Greg is gray' or 'Antoine is bored' but not both then Bernhard is a lion. We believe that if either 'Greg is gray' or 'Yann is hungry' but not both then Mary got the football.
Chances are about even that 'Mary got the football' or 'John went to the garden' or both.
Chances are about even that 'Mary got the football' or 'John went to the garden' or both.
It is almost certain that 'Mary got the football' or 'John went to the garden' or 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
  0.2::factA.
  0.7::factB.
  0.8::factC.
  %hop1
  0.2::factX:-xor(factA,factB).
  0.95::factY:-xor(factA,factC).
  0.75::factZ:-xor(factA,factB).

  %hop2
  conclusion:-or(factZ,factX).

  query(conclusion).
  
'Mary got the football' or 'John went to the garden' or both.