The Tao Is Silent is Raymond Smullyan's beguiling and whimsical guide to the meaning and value of eastern philosophy to westerners.   "To me," writes Smullyan, "Taoism means a state of inner serenity combined with an intense aesthetic awareness. Neither alone is adequate; a purely passive serenity is kind of dull, and an anxiety-ridden awareness is not very appealing."   This is more than a book on Chinese philosophy. It is a series of ideas inspired by Taoism that treats a wide variety of subjects about life in general. Smullyan sees the Taoist as "one who is not so much in search of something he hasn't, but who is enjoying what he has."   Readers will be charmed and inspired by this witty, sophisticated, yet deeply religious author, whether he is discussing gardening, dogs, the art of napping, or computers who dream that they're human.