Mindful that if it walks like a duck and quacks like a duck then it's a duck, form this point on we'll adopt the position that since the universe registers and processes information like a quantum computer and is observationally indistinguishable from a quantum computer, then it is a quantum computer. --Seth Lloyd
There is a nice review/reflection by Margaret Wertheim of MIT Professor Seth Lloyd's 'Programming the Universe: A Quantum Computer Scientist Takes on the Cosmos' (Knopf, March 2006) in today's LA Times Book Review section.
"Throughout history, humans have interpreted the world in terms of things they know. The ancient creator gods behaved like super-humans, coupling and breeding and giving birth to the cosmos, or fashioning its elements from familiar technologies such as weaving or molding clay. Modern scientific accounts also have drawn heavily on familiar contemporary tropes: In the 17th century, the universe was seen as a vast clockwork system. By the 19th, when the study of magnetic and electrical phenomena was hot, it was reconceived as a network of invisible force fields. At the dawn of the age of digital computers, scientists speculated that it was one of these machines," she muses.
"Inevitably, we see the whole through the lens of the particular. Though I do not doubt that the quantum computational view will yield new insights, history would suggest that a final metaphor is illusory. To reify that metaphor and insist the universe is a quantum computer seems almost as philosophically quaint as the Norse myth Lloyd describes in which "the universe begins when a giant cow licks the gods out of the salty lip of a primordial pit."