Thomas Aquinas

===Creation===
[[File:Tommaso - Super libros de generatione et corruptione - 4733257 00007.tif|thumb|''Super libros de generatione et corruptione'']]
{{further|abiogenesis|spontaneous generation}}

As a Catholic, Thomas believed that God was the "maker of heaven and earth, of all that is visible and invisible." But he thought that this fact can be proved by natural reason; indeed, in showing that it is necessary that any existent being has been created by God, he uses only philosophical arguments, based on his metaphysics of participation.<ref>See Thomas Aquinas, {{lang|la|Summa Theologiae}} I, q. 44, a. 1, co ([https://www.corpusthomisticum.org/sth1044.html#30287 Latin] and [https://isidore.co/aquinas/english/summa/FP/FP044.html#FPQ44A1THEP1 English])</ref> He also maintains that God creates {{lang|la|ex nihilo}}, from nothing, that is he does not make use of any preexisting matter.<ref>See {{lang|la|Summa Theologiae}} I, q. 44, a. 2 ([https://www.corpusthomisticum.org/sth1044.html#30291 Latin] and [https://isidore.co/aquinas/english/summa/FP/FP044.html#FPQ44A2THEP1 English]), and q. 45, a. 1 ([https://www.corpusthomisticum.org/sth1044.html#30320 Latin] and [https://isidore.co/aquinas/english/summa/FP/FP045.html#FPQ45A1THEP1 English])</ref> On the other hand, Thomas thought that the fact that the world started to exist by God's creation and is not eternal is only known to us by faith; it cannot be proved by natural reason.<ref>See {{lang|la|Summa Theologiae}} I, q. 46, aa. 1–2 ([https://www.corpusthomisticum.org/sth1044.html#30388 Latin] and [https://isidore.co/aquinas/english/summa/FP/FP046.html#FPQ46A1THEP1 English])</ref>

Like Aristotle, Thomas posited that life could form from non-living material or plant life:

{{blockquote|Since the generation of one thing is the corruption of another, it was not incompatible with the first formation of things, that from the corruption of the less perfect the more perfect should be generated. Hence animals generated from the corruption of inanimate things, or of plants, may have been generated then.<ref>{{cite book| author= Thomas Aquinas| title= Summa Theologica | chapter-url= https://www3.nd.edu/~afreddos/summa-translation/Part%201/st1-ques72.pdf |chapter= On the Work of the Sixth Day, Reply to Objection 5| translator=| via= NDPR}}</ref>}}
[[File:Tommaso d'Aquino – Super Physicam Aristotelis, 1595 – BEIC 4733624.jpg|thumb|''Super Physicam Aristotelis'', 1595]]
Additionally, Thomas considered [[Empedocles]]'s theory that various mutated [[species]] emerged at the dawn of Creation. Thomas reasoned that these species were generated through [[mutation]]s in animal [[sperm]], and argued that they were not unintended by [[nature]]; rather, such species were simply not intended for perpetual existence. That discussion is found in his commentary on Aristotle's ''[[Physics (Aristotle)|Physics]]'':

{{blockquote|The same thing is true of those substances Empedocles said were produced at the beginning of the world, such as the 'ox-progeny', i.e., half ox and half-man. For if such things were not able to arrive at some end and final state of nature so that they would be preserved in existence, this was not because nature did not intend this [a final state], but because they were not capable of being preserved. For they were not generated according to nature, but by the corruption of some natural principle, as it now also happens that some monstrous offspring are generated because of the corruption of seed.<ref>Saint Thomas Aquinas, [http://dhspriory.org/thomas/Physics2.htm#14 Physica] {{Webarchive|url=https://web.archive.org/web/20141228130315/http://dhspriory.org/thomas/Physics2.htm#14 |date=28 December 2014 }}, ''Book 2, Lecture 14'', Fathers of the English Dominican Province</ref>}}