It is probably not the case that Jessica is a mouse. It is unlikely that John picked up the apple. There is a better than even chance that Bernhard is a rhino. We doubt that if 'Bernhard is a rhino' or 'John picked up the apple' or both then Gertrude is a sheep. It is likely that if 'Bernhard is a rhino' or 'Jessica is a mouse' or both then Mary dropped the milk. It is probably not the case that if 'Jessica is a mouse and Bernhard is a rhino' then Julius is gray.
There is a better than even chance that 'Julius is gray and Bernhard is a rhino'.
It is highly unlikely that 'Julius is gray and Bernhard is a rhino'.
There is a better than even chance that 'Julius is gray and Bernhard is a rhino'.

  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
  0.25::factA.
  0.2::factB.
  0.6::factC.
  %hop1
  0.2::factX:-or(factC,factB).
  0.7::factY:-or(factC,factA).
  0.25::factZ:-and(factA,factC).

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

  query(conclusion).
  
'Julius is gray and Bernhard is a rhino'.