We believe that Julius is a lion. It is likely that Winona is a mouse. It is probable that Bernhard is white. It is probably the case that if either 'Winona is a mouse' or 'Bernhard is white' but not both then John discarded the milk. It is highly unlikely that if 'Bernhard is white and Julius is a lion' then Greg is a frog. It is highly likely that if 'Winona is a mouse and Bernhard is white' then Lily is green.
Chances are slight that 'Bernhard is white' or 'Greg is a frog' or both.
It is probable that 'Bernhard is white' or 'Greg is a frog' or both.
Chances are slight that 'Bernhard is white' or 'Greg is a frog' 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
  0.75::factA.
  0.7::factB.
  0.7::factC.
  %hop1
  0.7::factX:-xor(factB,factC).
  0.05::factY:-and(factC,factA).
  0.9::factZ:-and(factB,factC).

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

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