There is a better than even chance that Brian is a lion. There is a very good chance that Greg is gray. It is likely that Julius is a frog. We doubt that if 'Julius is a frog' or 'Brian is a lion' or both then Bill went to the kitchen. Chances are slight that if 'Brian is a lion' or 'Julius is a frog' or both then Lily is white. It is highly likely that if either 'Julius is a frog' or 'Brian is a lion' but not both then John discarded the apple.
Chances are about even that 'John discarded the apple and Lily is white'.
It is highly unlikely that 'John discarded the apple and Lily is white'.
Chances are about even that 'John discarded the apple and Lily is white'.

  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
  0.6::factA.
  0.8::factB.
  0.7::factC.
  %hop1
  0.2::factX:-or(factC,factA).
  0.1::factY:-or(factA,factC).
  0.9::factZ:-xor(factC,factA).

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

  query(conclusion).
  
'John discarded the apple and Lily is white'.