 Notice that even if my failure to rescue the child does not harm him, he is nonetheless harmed by drowning. After all, he would have been better off had he not fallen into the pond and drowned. This suggests a possible way for Mill to square Good Samaritan laws with the harm principle. Even if restrictions on A’s freedom, requiring him to benefit B, cannot be justified on grounds of preventing A from harming B, they may nonetheless be justified on the grounds of preventing harm to B. This draws our attention to a significant ambiguity in the harm principle (see Lyons 1979). Mill talks both about preventing one from harming others and about harm prevention. Indeed, his statement of the one very simple principle mentions both (OL I 9). But as the Samaritan example brings out, these two claims are not equivalent. Every time I prevent one person from harming another, I also engage in harm prevention. But some cases of preventing harm may not be cases of preventing one person from harming another. So we really should distinguish two different versions of the harm principle.