It is unlikely that Bernhard is a swan. It is probable that John picked up the apple. There is a better than even chance that Mary moved to the garden. There is a better than even chance that if either 'Mary moved to the garden' or 'Bernhard is a swan' but not both then Bill went to the kitchen. There is a better than even chance that if 'Bernhard is a swan' or 'Mary moved to the garden' or both then Julius is gray. There is a very good chance that if 'John picked up the apple and Bernhard is a swan' then Greg is a frog.
It is highly unlikely that 'Greg is a frog and Julius is gray'.
It is highly unlikely that 'Greg is a frog and Julius is gray'.
It is probably the case that 'Greg is a frog and Julius is gray'.

  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.
  0.7::factB.
  0.6::factC.
  %hop1
  0.6::factX:-xor(factC,factA).
  0.6::factY:-or(factA,factC).
  0.8::factZ:-and(factB,factA).

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

  query(conclusion).
  
'Greg is a frog and Julius is gray'.