This post is on an dir selbst as highlighted in this passage from chapter 'Der Fall Robinson' of Amerika (Der Verschollene) by Frankz Kafka. In this passage, Karl Rossmann is being cashiered at a hotel, and its Head Porter is addressing him.
»Es ist möglich«, fügte er [der Oberportier] hinzu und unterhielt sich dabei königlich, »daß du [Karl Rossmann] bei einem anderen Ausgang unbemerkt hinausgekommen wärest, denn du standest mir natürlich nicht dafür, besondere Anweisungen deinetwegen ergehen zu lassen. Aber da du nun einmal hier bist, will ich dich genießen. Im übrigen habe ich nicht daran gezweifelt, daß du das Rendezvous, das wir uns beim Haupttor gegeben hatten, auch einhalten wirst, denn das ist eine Regel, daß der Freche und der Unfolgsame gerade dort und dann mit seinen Lastern aufhört, wo es ihm schadet. Du wirst das an dir selbst gewiß noch oft beobachten können.«
QUESTION
Does it mean:
(a) in yourself: I.e. Karl is observing himself. The tendency to stop being vicious only out of self-interest (only when it hurts him) is in Karl. Karl will come to see that in himself often enough.
(b) on your own: I.e. Karl uses his own power of observation. The tendency is general though it may be in him too. Karl will come to see that for himself (and not have to take the Head Porter's word for it).
ADDENDUM
If the distinction between (a) and (b) is not clear (as an answer suggests), please consider these examples.
In yourself: You come of a line of soldiers, but want to be an artist. Your father says you would soon see the warrior in yourself. This expression locates soldier-likeness in you. You are soldier-like.
On your own: Your father says that the world only respects power, and you disagree. He says you will come to see the truth on your own (or for yourself, i.e. without anyone else having to tell you). Here, the expression is not locating respect for power anywhere in particular. The expression describes how you are going to see it. You may or may not respect power.
The question is, in which of the two situations you would use an dir selbst.