If this principle is accepted, however, it might seem that certain artists, and perhaps the greatest, might not fare well at our hands.  How would Shelley, for instance, stand such a test?  Every one knows the judgment passed on Shelley by Matthew Arnold, a critic who evidently relied on this principle, even if he preferred to speak only in the name of his personal tact and literary experience.  Shelley, Matthew Arnold said, was “a beautiful and ineffectual angel, beating his wings in a luminous void in vain.”  In consequence he declared that Shelley was not a classic, especially as his private circle had had an unsavoury morality, to be expressed only by the French word sale, and as moreover Shelley himself occasionally showed a distressing want of the sense of humour, which could only be called bete.  These strictures, if a bit incoherent, are separately remarkably just.  They unmask essential weaknesses not only in Shelley, but in all revolutionary people.  The life of reason is a heritage and exists only through tradition.  Half of it is an art, an adjustment to an alien reality, which only a long experience can teach:  and even the other half, the inward inspiration and ideal of reason, must be also a common inheritance in the race, if people are to work together or so much as to understand one another.  Now the misfortune of revolutionists is that they are disinherited, and their folly is that they wish to be disinherited even more than they are.  Hence, in the midst of their passionate and even heroic idealisms, there is commonly a strange poverty in their minds, many an ugly turn in their lives, and an ostentatious vileness in their manners.  They wish to be the leaders of mankind, but they are wretched representatives of humanity.  In the concert of nature it is hard to keep in tune with oneself if one is out of tune with everything.  We should not then be yielding to any private bias, but simply noting the conditions under which art may exist and may be appreciated, if we accepted the classical principle of criticism and asserted that substance, sanity, and even a sort of pervasive wisdom are requisite for supreme works of art.  On the other hand—­who can honestly doubt it?—­the rebels and individualists are the men of direct insight and vital hope.  The poetry of Shelley in particular is typically poetical.  It is poetry divinely inspired; and Shelley himself is perhaps no more ineffectual or more lacking in humour than an angel properly should be.  Nor is his greatness all a matter of aesthetic abstraction and wild music.  It is a fact of capital importance in the development of human genius that the great revolution in Christendom against Christianity, a revolution that began with the Renaissance and is not yet completed, should have found angels to herald it, no less than that other revolution did which began at Bethlehem; and that among these new angels there should have been one so winsome, pure, and rapturous as Shelley.