So Scientific American is doing metaphysics. Is this in its job description? That's hard to say; certainly quantum mechanics has many metaphysical implications, as does cognitive science. Perhaps I would have been more comfortable if Tegmark had bracketed his discussion with a commentary on the nature and value of untestable propositions--and if he had presented some of the alternative possibilities in a balanced manner.

Also useful might have been some grounding of the ideas in their very long, very thoroughly-investigated history. For instance, the ultimate vision of the universe that Tegmark presents is essentially identical to that presented by Olaf Stapledon in his novel Star Maker. It's a dizzying vision, to be true, and perhaps an uplifting one. In Stapledon's hands, it's essentially a religious notion. And this brings us to the nub of the issue.

The ultimate problem with doing metaphysics like this is not the untestable nature of the speculation; it's that untestable speculation always betrays the presence of an agenda on the part of the person doing the speculating. In this case, since these ideas are unprovable, one is forced to ask the question, "Why is it important to Tegmark to convince us that there are multiple univeses?"

Any answer will draw us away from science, into metaphysics, mysticism, Platonism etc. I'm not sure that this the proper agenda of Scientific American. On the other hand, Tegmark's ultimate agenda might be simple playfulness--and that, I wouldn't criticize.

The multiverse is a dangerous notion, however. Promoting it suggests a nihilistic agenda: the desire to destroy the significance of everyday life by proving the existence of an overwhelming, infinite set of alternatives. There's a Larry Niven story, "All the Myriad Ways" that explores the psychological devastation that proving such a notion could have.

The ultimate expression of the destructive power of the multiverse is to be found in Nietzsche, where he makes it the core of the notion of "eternal recurrence." His notion, described fully in the chapter The Vision and the Riddle of Thus Spake Zarathutra, is simple, and utterly shattering:

Hell and heaven are both real if every possible reality exists somewhere--and a version of you will end up in both of them. In fact, you're already there. Somewhere, you've won the Nobel prize, gotten the girl (or boy), been the first to walk on the moon... just not this 'you'. Everything will turn out right--just not for this version of you. Life will be fulfilling and meaningful--just not... you get the picture. You are doomed eternally to be just exactly what you are now, but with the extra knowledge that other versions of you exist somewhere that are succeeding at all the things you'll fail at, getting lucky where you missed the boat, and being honored where you're ignored. In an infinite multiverse, you are infinitely, unalterably sentenced to be reborn and live exactly this life, over and over again without escape, for eternity.

Sound good?

Unfortunately, Tegmark stops well short of contemplating such implications of the ideas he's propounding. This, I think, is a shame. Because he's essentially clothing a metaphysical argument in scientific trappings, and then not following through on its metaphysical implications.

Too bad--because his arguments might not just be convincing. If we can find some way of testing them, they might turn out to be right. And in that case, we'd better have a good idea how we're going to respond to knowing that the Multiverse is real.

<  |  >