Phish is not the next Grateful Dead, but the Phish scene is to the Grateful Dead’s something of what Volkswagen’s new Beetle is to the old: obedient but hardly servile; bolder, with more horsepower; slicker seeming, yet goofier when you think about it; a good idea to some, a bad one to others; an idea whose time has gone, or come. But not merely a replacement. Such things, to the people who hold them dear, the true groupies, are irreplaceable.