It is certain that John picked up the apple. Chances are about even that Fred moved to the office. It is certain that Bill went to the garden. We doubt that if either 'Bill went to the garden' or 'Fred moved to the office' but not both then Bernhard is yellow. There is a better than even chance that if 'John picked up the apple' or 'Fred moved to the office' or both then Julius is a lion. It is almost certain that if 'Bill went to the garden' or 'John picked up the apple' or both then Mary took the milk.
Chances are about even that 'Bill went to the garden' or 'John picked up the apple' or both.
It is certain that 'Bill went to the garden' or 'John picked up the apple' or both.
Chances are about even that 'Bill went to the garden' or 'John picked up the apple' 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
  1.0::factA.
  0.5::factB.
  1.0::factC.
  %hop1
  0.2::factX:-xor(factC,factB).
  0.6::factY:-or(factA,factB).
  0.95::factZ:-or(factC,factA).

  %hop2
  conclusion:-or(factC,factA).

  query(conclusion).
  
'Bill went to the garden' or 'John picked up the apple' or both.