It is highly likely that Winona is a cat. It is highly unlikely that Mary went to the kitchen. It is unlikely that Greg is a frog. We believe that if 'Greg is a frog and Mary went to the kitchen' then Julius is gray. We doubt that if 'Mary went to the kitchen' or 'Winona is a cat' or both then Lily is a lion. It is likely that if 'Mary went to the kitchen and Greg is a frog' then Bernhard is a swan.
There is almost no chance that 'Greg is a frog and Mary went to the kitchen'.
There is almost no chance that 'Greg is a frog and Mary went to the kitchen'.
Chances are about even that 'Greg is a frog and Mary went to the kitchen'.

  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
  0.9::factA.
  0.05::factB.
  0.2::factC.
  %hop1
  0.75::factX:-and(factC,factB).
  0.2::factY:-or(factB,factA).
  0.7::factZ:-and(factB,factC).

  %hop2
  conclusion:-and(factC,factB).

  query(conclusion).
  
'Greg is a frog and Mary went to the kitchen'.