He claims that the ancients, such as Aristotle, were unable to make that abstraction. "They were still trying to understand the whole world as it was".
...It was "obvious" to them that the first and most obvious property of moving objects was that they stopped moving once you stopped pushing them. An ox-cart rumbling down some rutted muddy path stopped when the oxen stopped pulling it; that was obvious, and the study of such was so mired in the nitty-gritty reality of the world that precious little progress was made until Galileo abstracted (I know, I know, I simplify: Oresme etc worked on the problem too and got some of the way there; but again, only by picking on simpler examples).Sorry, but that's quite horrible. The ancients such as Aristotle were well used to abstraction. Aristotle, as is well known, was profoundly influenced by Euclid and the abstract world of geometry, you know, perfect circles, spheres, lines, planes and so on. As was Plato before him, of course, who was so impressed with abstraction that he constructed a quasi-religious theory about it.
To get Newton's laws abstraction may be necessary, but not sufficient. The crucial part of Connolley's example is the 'friction' bit. We have to 'ignore friction'. Yes, but what is friction? Well, as we observe it with our own eyes in the natural world, it simply is the tendency of bodies in the sublunary world to slow down and stop. An ancient philosopher could easily have abstracted away friction, after all, that's exactly what Euclid did. There is no friction in Euclid's geometry, nor is there gravitation. But there's nothing in that abstraction that tells you what friction really is. The ancients thought that bodies slow down because that's what they naturally do, just as we think that bodies are naturally attracted to each other by gravitational force (which we still don't understand, except as some Aristotelian essential characteristic of matter).
The capacity to abstract is nothing to do with ancient science. In fact, the problem was too much abstraction. By contrast, a little more observation and attention to the actual world would have done the trick. As I observed here and elsewhere, it was Buridan's observation of milwheels and ships, plus a spell in an armchair, that led him to reject Aristotle's theory of impetus. Forget abstraction.