One's own free unfettered choice, one's own caprice-however...

One's own free unfettered choice, one's own caprice-however wild it may be, one's own fancy worked up at times to frenzy-is that very "most advantageous advantage" which we have overlooked, which comes under no classification and against which all systems and theories are continually being shattered to atoms... [an]will attain his object-that is, convince himself he is a man and not a piano-key!