It is probably the case that John got the apple. There is a very good chance that Lily is gray. It is probably the case that Julius is a rhino. It is probably the case that if 'John got the apple and Lily is gray' then Bernhard is a swan. We doubt that if either 'Lily is gray' or 'John got the apple' but not both then Mary went to the garden. There is a better than even chance that if either 'John got the apple' or 'Lily is gray' but not both then Brian is white.
It is probable that 'Julius is a rhino' or 'Mary went to the garden' or both.
It is probable that 'Julius is a rhino' or 'Mary went to the garden' or both.
It is probably not the case that 'Julius is a rhino' or 'Mary 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
  0.7::factA.
  0.8::factB.
  0.7::factC.
  %hop1
  0.7::factX:-and(factA,factB).
  0.2::factY:-xor(factB,factA).
  0.6::factZ:-xor(factA,factB).

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

  query(conclusion).
  
'Julius is a rhino' or 'Mary went to the garden' or both.