We cannot here expand the demonstration of the necessity and inevitability of this subjective criterion in every narrative of human affairs (which is compatible with the utmost objectivity, impartiality and scrupulousness in dealing with data of fact and indeed forms a constitutive element in these virtues), in every narrative of human doings and happenings. It suffices to read any book of history to discover at once the point of view of the author, if he be a historian worthy of the name and know his own business. There are liberal and reactionary, rationalist and catholic historians, who deal with political or social history; for the history of philosophy there are metaphysical, empirical, sceptical, idealist and spiritualist historians. Purely historical historians do not and cannot exist. Were Thucydides and Polybius, Livy and Tacitus, Machiavelli and Guicciardini, Giannone and Voltaire, wholly without moral and political views; and, in our time, was Guizot or Thiers, Macaulay or Balbo, Ranke or Mommsen? And in the history of philosophy, from Hegel, who was the first to raise it to a great height, to Ritter, Zeller, Cousin, Lewes and our Spaventa, was there one who did not possess his conception of progress and his criterion of judgement? Is there one single work of any value on the history of Æsthetic which has not been written from this or that point of view, with this or that bias (Hegelian or Herbartian), from a sensationalist or from an eclectic or some other point of view? If the historian is to escape from the inevitable necessity of taking a side, he must become a political or scientific eunuch; and history is not an occupation for eunuchs. Such would at most be of use in compiling those great tomes of not useless erudition, _elumbis atque fracta,_ which are called, not without reason, monkish. If, then, a concept of progress, a point of view, a criterion, be inevitable, the best to be done is not to try and escape from it, but to obtain the best possible. Every one tends to this end when he forms his own convictions, seriously and laboriously. Historians who profess to wish to interrogate the facts without adding anything of their own to them are not to be trusted. This is at best the result of ingenuousness and illusion on their part: they will always add something of their own, if they be truly historians, even without knowing it, or they will only believe that they have avoided doing so because they have conveyed it only by hints, which is the most insinuating, penetrative and effective of methods. [Sidenote: _Non-existence of a single line of progress in artistic and literary history._]