We doubt that Bernhard is gray. There is almost no chance that Julius is a swan. It is improbable that Jeff went to the garden. It is highly likely that if 'Jeff went to the garden and Bernhard is gray' then Sumit is thirsty. We believe that if 'Julius is a swan' or 'Jeff went to the garden' or both then Gertrude is a cat. We doubt that if 'Jeff went to the garden' or 'Julius is a swan' or both then Fred put down the apple.
There is little chance that 'Jeff went to the garden and Gertrude is a cat'.
There is little chance that 'Jeff went to the garden and Gertrude is a cat'.
It is highly likely that 'Jeff went to the garden and Gertrude is a cat'.

  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.
  0.02::factB.
  0.1::factC.
  %hop1
  0.9::factX:-and(factC,factA).
  0.75::factY:-or(factB,factC).
  0.2::factZ:-or(factC,factB).

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

  query(conclusion).
  
'Jeff went to the garden and Gertrude is a cat'.