All origins systems are underpinned by unprovable presuppositions, including atheistic origins accounts, the biblical origin account, and so on. Origins accounts have to be logically compatible with science and have explanatory power. Philosophical uniformitarianism is an atheistic presupposition. It is more in the realm of philosophy than science, yet it has a significant bearing on how atheists interpret scientific evidence, especially in the origins domain.

Christians and some prominent secular scientists agree that the origin of life on earth is a miracle. One group posits a Divine miracle. The other a secular miracle. Abiogenesis is foundational to the secular origins account. Before abiogenesis occurs, the mechanisms of biological evolution cannot be invoked. George Wald, Nobel Prize winner called abiogenesis both impossible and implied it was a miracle. Francis Crick implied it was a miracle. Fred Hoyle, atheist, calculated a probability for abiogenesis of 10 raised to the power of negative 40,000. Eugene Koonin in about 2012, invoked the multiverse as an infinity to try to make abiogenesis seemingly plausible. He calculated the probability of the RNA world hypothesis at less than 10 raised to the power of negative 1000. It has been labelled the hardest problem in biology. The most celebrated atheist of the twentieth century, Anthony Flew, left atheism when he realised the impossibility of abiogenesis and became a theist of some sort. If you need a miracle to explain abiogenesis, as these secular authorities have said, then the secular origins account is not as rigorously "scientific" as some might suppose.

That is broadly true, although there are creationist organisations within the Roman Catholic world. The major creationist organisations are evangelical (Protestant).