It is impossible that Brian is white. It is likely that Jeff moved to the office. It is probably not the case that Mary got the milk. Chances are about even that if 'Mary got the milk' or 'Brian is white' or both then Julius is a lion. It is likely that if 'Brian is white' or 'Jeff moved to the office' or both then Bernhard is a frog. It is likely that if 'Mary got the milk and Jeff moved to the office' then Jessica is a mouse.
Chances are about even that 'Bernhard is a frog' or 'Brian is white' or both.
Chances are about even that 'Bernhard is a frog' or 'Brian is white' or both.
It is highly unlikely that 'Bernhard is a frog' or 'Brian is white' 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
  0.0::factA.
  0.7::factB.
  0.25::factC.
  %hop1
  0.5::factX:-or(factC,factA).
  0.7::factY:-or(factA,factB).
  0.7::factZ:-and(factC,factB).

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

  query(conclusion).
  
'Bernhard is a frog' or 'Brian is white' or both.