We doubt that Julius is a rhino. It is probable that Bernhard is green. It is probably not the case that John got the milk. It is probable that if 'Julius is a rhino' or 'Bernhard is green' or both then Bill went to the garden. Chances are about even that if either 'Julius is a rhino' or 'John got the milk' but not both then Greg is a lion. There is little chance that if 'John got the milk and Bernhard is green' then Brian is a frog.
It is highly likely that 'Brian is a frog and Greg is a lion'.
It is impossible that 'Brian is a frog and Greg is a lion'.
It is highly likely that 'Brian is a frog and Greg is a lion'.

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

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

  query(conclusion).
  
'Brian is a frog and Greg is a lion'.