It is likely that Julius is a frog. There is almost no chance that Brian is green. It is highly likely that Mary dropped the apple. There is a better than even chance that if either 'Julius is a frog' or 'Mary dropped the apple' but not both then John picked up the milk. It is certain that if 'Brian is green' or 'Mary dropped the apple' or both then Bernhard is a lion. It is probably the case that if 'Brian is green' or 'Julius is a frog' or both then Jason is thirsty.
Chances are about even that 'Julius is a frog and Jason is thirsty'.
Chances are about even that 'Julius is a frog and Jason is thirsty'.
It is impossible that 'Julius is a frog and Jason is thirsty'.

  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.
  0.02::factB.
  0.9::factC.
  %hop1
  0.6::factX:-xor(factA,factC).
  1.0::factY:-or(factB,factC).
  0.7::factZ:-or(factB,factA).

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

  query(conclusion).
  
'Julius is a frog and Jason is thirsty'.