It is probable that Emily is a sheep. Chances are slight that Fred put down the apple. It is probable that Mary went to the garden. There is a very good chance that if either 'Emily is a sheep' or 'Mary went to the garden' but not both then Brian is a rhino. It is impossible that if 'Emily is a sheep and Fred put down the apple' then Lily is white. It is highly likely that if either 'Fred put down the apple' or 'Mary went to the garden' but not both then John left the milk.
Chances are slight that 'Emily is a sheep' or 'John left the milk' or both.
It is highly likely that 'Emily is a sheep' or 'John left the milk' or both.
Chances are slight that 'Emily is a sheep' or 'John left the milk' or both.

  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.
  0.1::factB.
  0.7::factC.
  %hop1
  0.8::factX:-xor(factA,factC).
  0.0::factY:-and(factA,factB).
  0.9::factZ:-xor(factB,factC).

  %hop2
  conclusion:-or(factA,factZ).

  query(conclusion).
  
'Emily is a sheep' or 'John left the milk' or both.