There is a very good chance that John went to the kitchen. Chances are about even that Brian is a lion. We believe that Jessica is a mouse. It is highly likely that if 'Jessica is a mouse' or 'John went to the kitchen' or both then Mary picked up the apple. Chances are slight that if 'Brian is a lion and Jessica is a mouse' then Greg is yellow. Chances are slight that if either 'John went to the kitchen' or 'Jessica is a mouse' but not both then Bernhard is white.
It is likely that 'Bernhard is white' or 'Greg is yellow' or both.
It is highly unlikely that 'Bernhard is white' or 'Greg is yellow' or both.
It is likely that 'Bernhard is white' or 'Greg is yellow' 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
  0.8::factA.
  0.5::factB.
  0.75::factC.
  %hop1
  0.9::factX:-or(factC,factA).
  0.1::factY:-and(factB,factC).
  0.1::factZ:-xor(factA,factC).

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

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