We doubt that Brian is a frog. It is probably not the case that Greg is yellow. It is certain that Bernhard is gray. There is a better than even chance that if 'Brian is a frog and Bernhard is gray' then Daniel left the milk. It is unlikely that if either 'Greg is yellow' or 'Brian is a frog' but not both then John took the football. Chances are about even that if either 'Bernhard is gray' or 'Brian is a frog' but not both then Lily is green.
There is almost no chance that 'Brian is a frog and John took the football'.
There is almost no chance that 'Brian is a frog and John took the football'.
It is highly likely that 'Brian is a frog and John took the football'.

  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.
  0.25::factB.
  1.0::factC.
  %hop1
  0.6::factX:-and(factA,factC).
  0.2::factY:-xor(factB,factA).
  0.5::factZ:-xor(factC,factA).

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

  query(conclusion).
  
'Brian is a frog and John took the football'.