Chances are about even that Greg is white. Chances are about even that Emily is a wolf. It is probably the case that John dropped the apple. Chances are about even that if 'John dropped the apple' or 'Emily is a wolf' or both then Mary moved to the garden. There is a very good chance that if 'Emily is a wolf and John dropped the apple' then Brian is yellow. We believe that if either 'John dropped the apple' or 'Greg is white' but not both then Bernhard is a lion.
We believe that 'Emily is a wolf and Bernhard is a lion'.
We doubt that 'Emily is a wolf and Bernhard is a lion'.
We believe that 'Emily is a wolf and Bernhard is a lion'.

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

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

  query(conclusion).
  
'Emily is a wolf and Bernhard is a lion'.