The Earth is flat . The Acropolis is in Athens. The Earth is flat. The Earth is round. Plato is a lousy philosopher.
Justification varies from person to person.
Notice furthermore that the individual statements never change the columns. Truth is objective. The conclusion is supposed to follow from the premises . It is usually indicated by a connective 'therefore', 'thus', 'hence', etc. The premises and conclusions of arguments can be true or false, justified or not, but never valid or invalid, sound or unsound.