It is probably the case that John moved to the garden. It is unlikely that Greg is green. It is improbable that Bernhard is a swan. There is a better than even chance that if either 'Greg is green' or 'Bernhard is a swan' but not both then Mary took the football. It is probably the case that if 'Bernhard is a swan' or 'Greg is green' or both then Sandra dropped the milk. It is improbable that if 'John moved to the garden and Bernhard is a swan' then Winona is a sheep.
It is impossible that 'Winona is a sheep and Sandra dropped the milk'.
It is impossible that 'Winona is a sheep and Sandra dropped the milk'.
Chances are about even that 'Winona is a sheep and Sandra dropped the milk'.

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

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

  query(conclusion).
  
'Winona is a sheep and Sandra dropped the milk'.