There is a very good chance that Jessica is a mouse. We doubt that Bernhard is a frog. It is likely that Greg is a lion. Chances are slight that if 'Greg is a lion and Jessica is a mouse' then Lily is a rhino. There is almost no chance that if 'Jessica is a mouse and Greg is a lion' then John took the apple. There is a very good chance that if 'Jessica is a mouse and Greg is a lion' then Mary went to the garden.
It is highly unlikely that 'Greg is a lion and Jessica is a mouse'.
There is a better than even chance that 'Greg is a lion and Jessica is a mouse'.
It is highly unlikely that 'Greg is a lion and Jessica is a mouse'.

  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
  0.8::factA.
  0.2::factB.
  0.7::factC.
  %hop1
  0.1::factX:-and(factC,factA).
  0.02::factY:-and(factA,factC).
  0.8::factZ:-and(factA,factC).

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

  query(conclusion).
  
'Greg is a lion and Jessica is a mouse'.