Chances are about even that Julius is gray. It is almost certain that Bill went to the kitchen. It is likely that Brian is a rhino. There is little chance that if 'Bill went to the kitchen' or 'Julius is gray' or both then Greg is a swan. There is little chance that if 'Bill went to the kitchen' or 'Julius is gray' or both then Gertrude is a sheep. There is a better than even chance that if 'Julius is gray and Bill went to the kitchen' then John got the milk.
It is probable that 'Gertrude is a sheep and Julius is gray'.
It is highly unlikely that 'Gertrude is a sheep and Julius is gray'.
It is probable that 'Gertrude is a sheep and Julius is gray'.

  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.
  0.95::factB.
  0.7::factC.
  %hop1
  0.1::factX:-or(factB,factA).
  0.1::factY:-or(factB,factA).
  0.6::factZ:-and(factA,factB).

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

  query(conclusion).
  
'Gertrude is a sheep and Julius is gray'.