Dan Barker on The fine-tuning argument
Barker argues that fine-tuning proves at most that the universe is compatible with life, not that it was designed for life.
Barker engages the fine-tuning argument by questioning its underlying assumptions. We do not know the range of possible values for physical constants, we do not know whether different constants would produce different forms of complexity, and we have a sample size of one universe — from which it is impossible to draw statistical conclusions about probability.
He also inverts the argument: rather than the universe being fine-tuned for life, life is fine-tuned for the universe. Evolution by natural selection produces organisms adapted to their environment, whatever that environment happens to be. If the constants were different, different forms of complexity might have emerged — we simply have no way of knowing. The anthropic principle explains why we observe a life-permitting universe: we could not observe any other kind.
Barker points to the same evidence that other critics emphasise: the universe is overwhelmingly hostile to life. If it were designed for us, the designer wasted 13.8 billion years and billions of light-years of lethal space. The fine-tuning argument works only if you ignore the 99.9999% of the universe that would kill any living thing instantly.
“The universe isn't fine-tuned for us. We are fine-tuned for it. That's what natural selection does.”