Chances are about even that Lily is white. It is improbable that Gertrude is a sheep. It is probably the case that Jeff went to the hallway. Chances are about even that if 'Jeff went to the hallway and Gertrude is a sheep' then John left the apple. It is probably not the case that if 'Gertrude is a sheep' or 'Lily is white' or both then Fred is in the office. There is almost no chance that if either 'Lily is white' or 'Gertrude is a sheep' but not both then Jason is tired.
It is highly likely that 'Jason is tired and John left the apple'.
It is impossible that 'Jason is tired and John left the apple'.
It is highly likely that 'Jason is tired and John left 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
  0.5::factA.
  0.1::factB.
  0.7::factC.
  %hop1
  0.5::factX:-and(factC,factB).
  0.25::factY:-or(factB,factA).
  0.02::factZ:-xor(factA,factB).

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

  query(conclusion).
  
'Jason is tired and John left the apple'.