Spontaneous Generation

The 1859 experiment of Louis Pasteur is widely credited with formally settling, as much as mere sensory observations can, that it is exposure to outside factors that brings organisms to feed on some body of matter, such as maggots with meat.  Today, the position with the most empirical support is that, in the previously mentioned example, it is really that flies are attracted by scent to dead flesh, and the maggots which appear are their offspring from eggs placed in/on the meat, which in turn consume it.  The formerly prominent doctrine of spontaneous generation held that a substance like meat created or perhaps transformed into living creatures as with dead flesh and maggots, or cheese and mice.

The more modern conception of abiogenesis would require that the first life, now commonly proposed to be only organic molecules, did indeed come from nonliving matter, and some assume that this concept would render all forms of theism false if true or that the falsity of spontaneous generation would necessitate that of abiogenesis in the distant past.  This idea of life coming from non-life actually does not contradict theism (which is both more philosophically fundamental and broader in variety than a religion like Christianity) and more importantly does not contradict reason, the axioms of which are the only things that cannot be anything but true in themselves, because of themselves, without reliance on any other metaphysical realities.  As such, since only logical axioms like the fact that something must true (if not, the alternative would still be true!) have to be correct, only things that conflict with them are genuinely impossible.

Just because abiogenesis is logically possible does not mean it ever occurred or will, of course, for this does not follow.  However, abiogenesis in this narrower sense does not require ongoing spontaneous generation such as the kind by which dust would give rise to fleas or dirt to worms.  Rather, life would only have to emerge from nonliving particles once.  With macro-evolution, which is not about the origin of life but its development across generations of organisms over time, life evolves from one round of offspring to another: there is already life or else evolution could not occur in the first place, for there would be no living things to adapt or reproduce.  The typical conception of spontaneous generation being false would not entail the same for a singular, initial event of abiogenesis, and evolution does not logically require primordial biogenesis or abiogenesis specifically.

Neither abiogenesis nor evolution excludes direct theistic creation of the basic matter of the cosmos, or else they would be false by necessity since there cannot not be an uncaused cause in light of the impossibility of an infinite past (and thus an infinite number of past material events or an infinite age of the universe), of self-creation (something would have to exist before it existed to create itself), and of something coming into existence without a cause.  It is just that the universe can be created without life present but with the metaphysical and logically possible capacity to somehow eventually produce life left to itself.  Following hypothetical abiogenesis, there is nothing about evolution that excludes God guiding the development of life after it began, though it came about without any sort of direct creation by a mind.  It is likewise possible for God to have created the first life form(s) and allowed it to evolve unguided or with his involvement.

More foundationally, once again, since only consistency with logical axioms and other necessary truths makes something possible (for instance, the idea of one scientific law might contradict another that is genuinely true, but it could have been the case that the alternative was true and only the inverse law of nature was in existence), abiogenesis is not impossible because logical axioms would still be true in themselves by self-necessity.  Concerning current empirical observation and the evidence against spontaneous generation, not even trillions of years of the same basic natural processes would logically necessitate that abiogenesis being contingently impossible at one time or in a certain context means it is impossible at all other times.  This would be an instance of the induction fallacy.  As long as nothing contradicts the intrinsic truths of reason, however unusual it would be compared to our sensory experiences or evidential expectations, it is possible, as with abiogenesis even if spontaneous generation as popularly conceived is wholly erroneous.  Rationalism and core theism are unaffected no matter what.