That’s like saying that in order for temperature to be a fixed figure which depends on pressure, which is what you need for condensation to be a thing, every mo

That’s like saying that in order for temperature to be a fixed figure which depends on pressure, which is what you need for condensation to be a thing, every molecule needs to be exactly as likely to collide with every other molecule. Therefore liquid/gas can’t be a binary state. Phase transitions in large scale systems resulting from changes in the average behavior of individual elements are a real thing. An infection is an unstable dynamic system which tends to different states depending on whether the mean R is greater or less than one.