Do you know about the mathematical or logical idea of sets which is also called set theory? Is your "field/where" like a set and your "what" like a subset of your "field/what" set?
Example: Take a set of all fruits(this means make a list of all different kinds of fruits). Now you have a set containing the names of all fruits. A subset of your set of fruits is defined to be any list which contains only names taken from your set of fruits. So, if I made a list containing banana, lemon and apple it would be a subset of a set of all fruits....but if I made a lost containing banana, orange and craving then this would NOT be a subset of a set of all fruits because craving does not appear in the set of all fruits. In this example the set of all fruits would be called the superset and any set containing only things taken from the list of all fruits (the superset) would be called a subset......specifically it would be called a subset of the set containing all the fruits.
So, are you saying, for example, that the Buddha starts by talking about the superset of craving and then changes focus to a particular subset of craving to focus in on the issue at hand?
I have a vague memory of sets in math. I have probably confused this in past posts but to set it straight now: a field is a "where", which is different from the way we define things, which is a "what".
But, in part, yes. The thing is that the field I am talking about, as the Buddha uses it, has two different purposes and two different meanings. One purpose/meaning is as a mathematical set, as you say. Out of the set of all forms of craving, he is addressing as problematic only a subset of craving. So that is one definition of the field -- the field as a set.
But the other way he uses the field is more literally as a field -- something in which something else grows -- or more specifically, something that is necessary in order for the thing we are really concerned with to happen -- a least-proximate (but usually quite large, and certainly significant) cause. The thing that astounds me about the way he uses these is that they are always related, always inextricably intertwined. It would never in a million years occur to me to do what he did with them but it sure works beautifully.
So for example if he defines dukkha as (the large set of) birth, aging, sickness, and death he is:
(1) Describing the complete set within which we find dukkha -- it happens inside of birth, aging, sickness and death.
(2) Simultaneously pointing out that those things are *fodder* (nutriment -- the ground that the field is made up of) for the growth of dukkha -- as indeed, they are, as they represent impermanence.
I tend to use the word "field" because it covers both. If we recognize that what's being talked about is a big plot of dirt that nurtures something that grows, when we point to that field over there, the field includes the ground, and everything that grows in it -- it's the big complete set. And an agricultural given in that description of a field is that some of the stuff that grows is worth keeping, and some is not (subsets); even the extra add-ins in the field are subsets (seeds blown in, cow dung, rain landing). But what we are concerned with is making sure we know why what's growing grows, so that we can nurture the good stuff correctly, and discourage the bad stuff -- but we aren't going to do away with the ground, it's just there.