Wittgenstein says in OC that there is no intermediary between the source of a pain and the pain, i.e., between a pencil jabbed in your hand and the feeling of pain (417). I take this point to related to Wittgenstein's writing in the PI about pain--both the certainty of one's own pain and the certainty with which one acts when faced with someone else in pain. (I apologize for lacking the relevant section citations for this part.)
For instance, you never doubt that you're actually in pain. And if your friend exhibits action that you associate with pain--falling down and writhing, making that face, shrieking--then you aid him. It seems as if you act without an intermediate step; you act without thinking, as it were. It seems like feeling pain and one's reaction to another's feeling pain can be conflated.
Consider what you do when you're in pain. If you stub your toe: You may grab it, hop around or curse. If you cut your hand: You wrap it in a towel or apply pressure. If you fall down on your elbow: You probably rub it or brush away any debris from the cuts and scratches. Consider what you do when other people are in pain. If someone falls down: You go over to him and ask if he's ok, help him up. If someone cuts himself: You offer a towel or a bandage. And so forth. Generally you act with certainty in both situations. (The amount of certainty is irrelevant, nonsensical.)
I think the ethical argument one could extrapolate here is this: In certain cases you act with no intermediary. In cases of someone being in pain and in cases of ethical dilemma. You simply act. If someone needs help crossing the street, you do not doubt if he really needs help crossing the street: You help him across the street. This view is directly opposed to the Kantian ethical view in the GMM. The outcome is of prime importance, not the end or intention. I've always thought the Kantian perspective on ethics placed actual ethical action in the backseat to a metaphysical/religious notion of dignity and contemplation. You meet many people in a day, and can you will the maxim of not killing each? Is this something you contemplate? Do you try to legislate your kingdom of ends? Don't you just act?
A macro and micro level of ethical action. The latter: global politics; legislation; legal rulings. The former: helping someone across the street; giving a friend some change for the meter. It seems like one acts in the former sense many times every day--without thinking. Thought, satisfaction, critique are all epiphenomena of the ethical action. But larger ethical actions such as the decision to go to war, to execute someone, to ban abortion: These actions bear some deliberation in the Aristotelian/Kantian sense. How can we reconcile this apparent discrepancy? Does the earlier section of OC, in which Wittgenstein seems to be writing about a coherence model of epistemology bear on this question? (Benjamin seems to think so.) I'm not sure if one can conflate ethics and epistemology.