It is probable that Brian is a frog. It is almost certain that Julius is white. It is almost certain that Greg is a lion. We doubt that if 'Julius is white' or 'Greg is a lion' or both then Gertrude is a mouse. It is probably not the case that if 'Greg is a lion' or 'Brian is a frog' or both then Jeff moved to the office. There is a better than even chance that if 'Brian is a frog' or 'Julius is white' or both then Lily is yellow.
Chances are slight that 'Brian is a frog' or 'Jeff moved to the office' or both.
We believe that 'Brian is a frog' or 'Jeff moved to the office' or both.
Chances are slight that 'Brian is a frog' or 'Jeff moved to the office' 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
  0.7::factA.
  0.95::factB.
  0.95::factC.
  %hop1
  0.2::factX:-or(factB,factC).
  0.25::factY:-or(factC,factA).
  0.6::factZ:-or(factA,factB).

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

  query(conclusion).
  
'Brian is a frog' or 'Jeff moved to the office' or both.