On Fine-Tuning and the Multiverse

The Fine-Tuning Problem

I've been thinking a lot lately about the problem of fine-tuning and how it may or may not be resolved by appeal to a multiverse. This has been prompted by recent correspondence with the philosopher Philip Goff and by the book I am currently reading, The Beginning of Infinity by David Deutsch. I hope to get around to discussing Deutsch's ideas in future, but for now I'm focusing on an argument put forth by Roger White and endorsed by Goff.

The fine-tuning problem is just that the laws of physics describing the universe seem to be fine-tuned so as to allow life to exist. While trying not to be too parochial in our assumptions about what life requires to exist, at least in a universe even vaguely like ours, it seems reasonable to assume that it must at least have time and a stable environment in which to evolve, access to sources of energy and a varied assortment of building blocks from which to assemble itself.

But if the physical constants were slightly different, then perhaps stars, heavier elements or atoms could not have formed. Perhaps the universe would never have expanded from its initial hot, dense state, or would have recollapsed too quickly, or perhaps it would have expanded too quickly for particles to come together at all. When we say the universe appears to be fine-tuned, we are claiming that it appears to be delicately balanced so as to allow complex evolving self-replicators (i.e. life) to exist -- that almost any tweak we imagine to the constants or the laws of physics would result in a simpler, lifeless universe. This curious observation seems to demand an explanation.

A part is more complex than the whole

Here's two apparently unrelated hypotheses for you:

1. The universe contains infinite space and an infinite quantity of stuff.

2. The many worlds interpretation of quantum mechanics is true.

Both of these appear at first glance to be astonishingly wasteful, positing infinities upon infinities of things we can never observe and which can never affect us. As such, they appear to be more complex than ideas which assume that space is finite or that there is only one quantum world.

It would seem that Occam's razor weighs against them.

In this post, I will argue that in fact the reverse is true.