It is likely that Gertrude is a sheep. It is certain that Julius is a lion. It is probable that Fred is in the cinema. It is certain that if either 'Julius is a lion' or 'Gertrude is a sheep' but not both then John dropped the apple. There is a very good chance that if 'Julius is a lion' or 'Gertrude is a sheep' or both then Bernhard is green. There is little chance that if 'Gertrude is a sheep' or 'Fred is in the cinema' or both then Daniel got the milk.
It is impossible that 'Gertrude is a sheep and John dropped the apple'.
It is impossible that 'Gertrude is a sheep and John dropped the apple'.
It is probably the case that 'Gertrude is a sheep and John dropped the apple'.

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

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

  query(conclusion).
  
'Gertrude is a sheep and John dropped the apple'.