It is probably the case that Lily is a rhino. There is little chance that Jason is thirsty. It is probably the case that Bernhard is a lion. Chances are slight that if either 'Jason is thirsty' or 'Lily is a rhino' but not both then Brian is white. It is unlikely that if 'Lily is a rhino' or 'Jason is thirsty' or both then John picked up the milk. Chances are about even that if 'Bernhard is a lion and Jason is thirsty' then Greg is a rhino.
It is highly likely that 'Lily is a rhino and Greg is a rhino'.
There is almost no chance that 'Lily is a rhino and Greg is a rhino'.
It is highly likely that 'Lily is a rhino and Greg 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
  0.7::factA.
  0.1::factB.
  0.7::factC.
  %hop1
  0.1::factX:-xor(factB,factA).
  0.2::factY:-or(factA,factB).
  0.5::factZ:-and(factC,factB).

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

  query(conclusion).
  
'Lily is a rhino and Greg is a rhino'.