In the First Way STA understands the motion as an educare. The Latin term had already developed in STA’s time to its familiar English meaning as education,* and so we should take the act of teaching/ learning as the paradigm to understand where we start from in the First Way.
Early Modern philosophy shifted the paradigm sense of motion from raising (educare) a child or animal or crop to something like one billiard ball hitting another. While something like this had to happen if we wanted to develop an experimental physics, the shift affects a difference that is hard to overstate. We move from a sense of nature that is understood best by a teacher, husbandman, farmer and gardener to one understood best by an engineer or artisan. We shift from experience to experiment. While in both cases the thing that causes motion has some actuality or power that the subject in motion lacks, we shift from a sense that agency is at the service of the mobile subject to an agency that dominates and controls its activity. In the first sense of motion the ideas of natural and violent have some place and the subjective mobile has all sorts of interesting structure and needs that have to be taken into consideration in order for the motion to happen while in the second sense the mobile subject is so evacuated of structure that Newton doesn’t even bother to name it. At most it is a body, but it is entirely and perfectly responsive to “force”. The distinction between natural and violent motion becomes largely unimportant to the physicist.
Or does it? A closer look at the foundations of mathematical physics shows that it’s based on the idea that falling is a natural local motion. One could write a very impressive history of modern physics as a development of the insight that bodies fall by nature. This is what Newton saw in the apple, and Einstein developed in the equivalence principle that founds GR. Force or energy is an educatio of the natural desire of a body to fall.
In Aristotle, natural motion seemed to be for rest in natural place. Newton changed this by seeing natural bodies as having an operatio to fall, which is the actualization of its gravitas or gravity. Rest, whether in a natural place or not, was not what body is trying to do – it was rather trying to actualize it’s gravitas. Nevertheless, in order to articulate this actualization he had to set it in opposition to a state of rest, even though there was no clear sense in his system of why rest could ever be a meaningful action for a natural body. Einstein’s equivalence principle does away with the need to oppose the acceleration of gravitas and rest by treating them as equivalent.
*At least in the broad sense of “bringing up” or “raising” a child, though it extends easily to animals and crops. The traditional way of giving the goal of marriage is as educatio proles, the raising of children (which was understood to usually include their generation).