It is probably not the case that Lily is a swan. It is highly unlikely that Bernhard is yellow. There is a very good chance that John went to the garden. It is highly unlikely that if 'Lily is a swan and Bernhard is yellow' then Jason is bored. There is a very good chance that if either 'Bernhard is yellow' or 'Lily is a swan' but not both then Brian is a frog. Chances are slight that if 'Bernhard is yellow and John went to the garden' then Julius is a lion.
There is a very good chance that 'John went to the garden' or 'Bernhard is yellow' or both.
There is a very good chance that 'John went to the garden' or 'Bernhard is yellow' or both.
We doubt that 'John went to the garden' or 'Bernhard is yellow' 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
  0.25::factA.
  0.05::factB.
  0.8::factC.
  %hop1
  0.05::factX:-and(factA,factB).
  0.8::factY:-xor(factB,factA).
  0.1::factZ:-and(factB,factC).

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

  query(conclusion).
  
'John went to the garden' or 'Bernhard is yellow' or both.