  Hence, as was to be desired, if the defined relation of logical consequence holds for a given pair &lt;K, X&gt;, then also condition (F) holds for it.  (Although this can be shown, the converse cannot; that is, it cannot be shown that if X and K satisfy (F) then X follows from K according to Tarski’s definition. But this is all right, since, as Tarski has already pointed out, (F) is not a sufficient condition for the ordinary notion of consequence.)