There are two hypotheses for an explanation for the fine-tuning (FT) of nomic behavior we observe, which permits the existence of intelligent life. These hypotheses are that there is a fine-tuner responsible for causing the nomic behavior and a non-fine-tuner hypothesis–anything but a fine-tuner.
The two competing hypotheses rise and fall on the same crux. One of the problems with falsifying ~FT is that whatever falsifier may be presented it could always be attributed to this idea of cosmic Darwinism, the evolution of the multiverse itself. Paul Davies criticizes the multiverse because he believes it could never be falsified simply because many worlds can be used to explain anything. Science would become redundant and the regularities of nature would need no further investigation, because they could simply be explained as a selection effect, need to keep us alive and observing.