St. Thomas argued that every naturally necessary being was being created by God, which meant the direct creation of elements, the celestial bodies, and the human soul. We mean more or less the same thing by “soul” as he did, but our ideas of elements and of celestial bodies have changed in various ways.
Elements: For STA, these were the simplest and most fundamental species of material causes. What we now call elements are composites of simpler material causes, and so they do not count as examples of what St. Thomas called an element. For us, the term “element” is for us a relic of an earlier time when we thought the things we were talking about (carbon, oxygen) were the simplest material causes. It’s not clear what in modern cosmology counts as a thomistic “element” or whether something field-like or particle-like is playing this role. What we are looking for is something that makes more complex things and is itself ungenerated, where “ungenerated” means something more than the element’s transition from a virtual to an actual presence. For example, I can make a pile of carbon from all sorts of organic things, but this is not the same thing as making carbon in the heart of a dying star. The latter, however, is generation in a true sense and therefore proves that carbon cannot count as an element in the ancient/medieval sense.
Heavenly bodies. This translation is more straightforward. In the ancient/medieval tradition these were the sources of motion in corruptible things, which means that they played the role now played by energy.
Both the elements and the heavenly bodies/ energy are necessary beings and essentially incorruptible. Just as the heavenly bodies could only change place and this change of place was at the foundation of an absolutely necessary system, so too energy can only change modes and it stands at the foundation of a closed system and can neither be generated nor pass away. So too the “fundamental particles” (if there are such things) are not generated or corrupted from any more fundamental material reality.
Now it has always been a separate question whether the source of motion and the elements are distinct in substance. For the ancients, the question had an obvious answer since the elements were down here and the sources of motion and work were up there. But for us, the question is far more complicated. The function played by the heavenly bodies has been made immanent to things, which raises the question whether this function is being played by a reality that is not really distinct in being from the elements.
And so we run into a pretty common problem that ancient physics was very good at seeing the sorts of things that were logically necessary in a physical theory even though they were wrong about the things that played these roles while we, on the other hand, have all sort of fantastic data to answer the question but can’t figure out what is playing what role.