Today I saw the phrase "not random, but undirected" and think it is probably a good high-level summary of the Epicurean position in physics, given that the properties of the elemental particles give rise to their motions, while at the same time the concept of "the swerve" is also operational, but that none of this is "random" in the sense of "chaotic" or "subject to fortune." The key is in the definitions of these words, but the issue is that Epicurus was concerned to explain the observed regularity of the universe while still preserving a mechanism for free will, and it helps to have ways to capture this attack on both religion and radical skepticism in a single phrase.
This subforum and thread are set up to discuss that. I have googled for the phrase without finding this precise formulation very often (if at all) but here is a clip from an article that is very close - discussing animal behavior. The book is "Animal Behavior" by Michael D. Breed and Janice Moore; this context of animals is no doubt not a perfect analogy, but there are other examples relating to "undirected graphs" and other aspects of mathematics which are probably better, but I don't have those at hand.
I also think this is probably closely related to the matters discussed in "Chance and Natural Law in Epicureanism" by AA Long.
For the time being, this is more a placeholder than an assertion of a conclusion...