 Later versions of the double effect principle all emphasize the distinction between causing a morally grave harm as a side effect of pursuing a good end and causing a morally grave harm as a means of pursuing a good end. We can summarize this by noting that for certain categories of morally grave actions, for example, causing the death of a human being, the principle of double effect combines a special permission for incidentally causing death for the sake of a good end (when it occurs as a side effect of one’s pursuit of that end) with a general prohibition on instrumentally causing death for the sake of a good end (when it occurs as part of one’s means to pursue that end). The prohibition is absolute in traditional Catholic applications of the principle. Two traditional formulations appear below.