What is a skopos in Aristotle? A mark, target, goal? Is it only that?
The question was raised in my mind when looking at the end of Met. I.2: "We have said, then, what is the nature of our sought-after knowledge, and what is the mark (skopos) which this investigation and plan of inquiry ought to hit."
Clearly, Aristotle explains the nature (phusis) of this knowledge, wisdom, in chapter 1: It is, as he says, a knowledge of first principles and first causes. But what has Aristotle said about the skopos of the investigation? (Presumably, the skopos is different from the phusis.)
ti/j me\n ou)=n h( fu/sij th=j e)pisth/mhj th=j zhtoume/nhj, ei)/rhtai, kai\ ti/j o( skopo\j ou(= dei= tugxa/nein th\n zh/thsin kai\ th\n o(/lhn me/qodon.
Suppose that what Aristotle says in chapter 2 concerns the skopos. But in I.2 he says such things as that: the search for this knowledge is motivated, not by practical necessity, but by wonder (982b11-22), and that the search ends when we arrive at a confident understanding of how what previously was wondered at is in fact necessary (983a12-21). Also, that the search ends when we've traced causes back as far as something divine (982b28-983a11).
That is to say, what he tells us in I.2 concerns how we know that we've arrived at it. That chapter gives us marks, or criteria, for recognizing that we've finally got hold of what we were searching for.
But, if so, then a skopos is not merely a 'target'. One thinks of a skopos as something like a bullseye--it is what one at the start aims at, or takes as a goal once and for all. The arrow either hits that target or not. But Aristotle seems to think of it, rather, as something which tells us whether we are reaching the target or not. It would be more like the sighting of the target within a 'scope'. Indeed, as he elsewhere says, the skopos is "that with a view to which we make adjustments, tightening or loosening", e)pitei/nei kai\ a)ni/hsin (e.g. NE 1138b22) --that is, continuously so.
Here is an analogy. Suppose someone is on a treadmill machine at the gym. He wants to get a 'cardio' workout and maintain his heartbeat at 140 beats per minute. To do so, he holds onto sensors on the railing of the machine, which register his heartbeat: when his heartbeat is at 140, a red light goes on; when the heartbeat goes above or below, the red light goes off.
On this picture, his goal and target is to keep his heartbeat at 140 beats per minute (since that is what is best for conditioning his heart). But his skopos is that the red light remain on: the light confirms that he's reached his goal.