It’s true that extremophile bacteria are still “life as we know it” in a fundamental biochemical sense–they use nucleic acids and proteins (albeit some proteins that are used by no other form of life on Earth) and water (although they may live in very salty water, or acidic water, or alkaline water, or hot water, or have some neat biochemical tricks for keeping that water from freezing solid). The point about the so-called “Anthropic Principle”, I think, is that its proponents, when they claim that the Universe is “fine tuned” in its various physical constants to produce little old us, implicitly assume that whales and trees and bacteria are all just byproducts of some kind. In order to have human beings (the pinnacle of creation, naturally), you happen to wind up with a Universe with whales and trees and bacteria. But it may be that, in “fine-tuning” a Universe which produces bacteria, some of those bacteria will inevitably begin to clump together and achieve endosymbiosis and so on and eventually turn into trees and whales and human beings. Maybe we are the byprodcts, and it’s really the Bacterial Principle, not the Anthropic Principle at all.
And maybe it’s not even bacteria. Maybe, in “fine tuning” the Universe to produce stable objects undergoing thermonuclear fusion reactions at their cores–in setting the laws of gravity and the nuclear forces such that those forces can balance out and such objects can exist for extended periods without blasting themselves apart on the one hand or imploding on the other–in making such a Universe, inevitably some of the fusion reactors will produce heavier elements, some of which will wind up in other fusion reactors (often as essentially “useless” contaminants), but some of which will wind up in objects too small to do anything else “useful” (i.e., undergo fusion reactions), and on some of those objects, complex self-replicating chemical reactions will begin to take place. Maybe the “purpose” of the Universe is to make stars and galaxies, and all life is just a waste product of this process.
If the Universe weren’t “fine tuned” to be the way it is–if its physical laws were different–it wouldn’t contain life, at least not life as we know it. It also wouldn’t contain stars, at least not stars as we know them. Or planets (as we know them). Or interstellar dust clouds, comets, the volcanoes of Io, the element rubidium, Martian dust storms, pulsars, snowflakes, quasars, or gamma ray bursters.
In short, the “Anthropic Principle” seems to me to be little more than a fancy way of saying “If the Universe weren’t the way it is, it would be different”.
