Chances are about even that Brian is a rhino. It is certain that John moved to the office. There is almost no chance that Greg is white. It is highly unlikely that if either 'John moved to the office' or 'Greg is white' but not both then Winona is a cat. We doubt that if 'Greg is white' or 'John moved to the office' or both then Mary left the football. It is likely that if 'Greg is white and John moved to the office' then Fred discarded the apple.
It is probably the case that 'Fred discarded the apple and Brian is a rhino'.
It is impossible that 'Fred discarded the apple and Brian is a rhino'.
It is probably the case that 'Fred discarded the apple and Brian is a rhino'.

  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
  0.5::factA.
  1.0::factB.
  0.02::factC.
  %hop1
  0.05::factX:-xor(factB,factC).
  0.2::factY:-or(factC,factB).
  0.7::factZ:-and(factC,factB).

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

  query(conclusion).
  
'Fred discarded the apple and Brian is a rhino'.