It is probable that Bernhard is yellow. It is likely that Lily is a swan. It is probably not the case that John moved to the garden. It is probably not the case that if 'Lily is a swan' or 'Bernhard is yellow' or both then Daniel left the apple. There is little chance that if 'Lily is a swan' or 'Bernhard is yellow' or both then Gertrude is a sheep. It is certain that if 'Bernhard is yellow and Lily is a swan' then Julius is a swan.
We believe that 'Julius is a swan and Gertrude is a sheep'.
It is highly unlikely that 'Julius is a swan and Gertrude is a sheep'.
We believe that 'Julius is a swan and Gertrude is a sheep'.

  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.
  0.7::factB.
  0.25::factC.
  %hop1
  0.25::factX:-or(factB,factA).
  0.1::factY:-or(factB,factA).
  1.0::factZ:-and(factA,factB).

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

  query(conclusion).
  
'Julius is a swan and Gertrude is a sheep'.