It is highly unlikely that Bernhard is a swan. It is unlikely that Gertrude is a cat. There is a very good chance that Mary moved to the garden. It is highly unlikely that if 'Bernhard is a swan and Gertrude is a cat' then Julius is gray. It is probably not the case that if 'Mary moved to the garden and Bernhard is a swan' then John dropped the apple. We believe that if either 'Gertrude is a cat' or 'Mary moved to the garden' but not both then Brian is white.
Chances are slight that 'Gertrude is a cat' or 'Brian is white' or both.
It is probable that 'Gertrude is a cat' or 'Brian is white' or both.
Chances are slight that 'Gertrude is a cat' or 'Brian is white' 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
  0.05::factA.
  0.2::factB.
  0.8::factC.
  %hop1
  0.05::factX:-and(factA,factB).
  0.25::factY:-and(factC,factA).
  0.75::factZ:-xor(factB,factC).

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

  query(conclusion).
  
'Gertrude is a cat' or 'Brian is white' or both.