It is probably not the case that Bernhard is a frog. It is certain that Greg is green. It is improbable that Brian is a swan. Chances are about even that if 'Brian is a swan' or 'Greg is green' or both then Emily is a cat. It is likely that if 'Brian is a swan' or 'Greg is green' or both then Daniel dropped the apple. It is highly unlikely that if either 'Bernhard is a frog' or 'Brian is a swan' but not both then Gertrude is a cat.
It is almost certain that 'Bernhard is a frog and Greg is green'.
It is probably not the case that 'Bernhard is a frog and Greg is green'.
It is almost certain that 'Bernhard is a frog and Greg is green'.

  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.
  1.0::factB.
  0.1::factC.
  %hop1
  0.5::factX:-or(factC,factB).
  0.7::factY:-or(factC,factB).
  0.05::factZ:-xor(factA,factC).

  %hop2
  conclusion:-and(factA,factB).

  query(conclusion).
  
'Bernhard is a frog and Greg is green'.