"principle of double effect" opens a slippery slope, see ectopic pregnancies

I am going to try and understand my opponents arguments, though I will admit that they are a little confusing. Let's break this down bit by bit without making it too complicated shall we? For those of you who don't know what the "double effect", the Stanford encyclopedia of philosophy gives a pretty good definition. The doctrine (or principle) of double effect is often invoked to explain the permissibility of an action that causes a serious harm, such as the death of a human being, as a side effect of promoting some good end. http://plato.stanford.edu... In lamens terms "We meant good, but oopsied". So 's get to why The principle of double effect isn't a slippery slope. Argument 1: Definition differentials. The proper explanations behind the slippery slope is: The Slippery Slope is a fallacy in which a person asserts that some event must inevitably follow from another without any argument for the inevitability of the event in question. In most cases, there are a series of steps or gradations between one event and the one in question and no reason is given as to why the intervening steps or gradations will simply be bypassed. http://www.nizkor.org... In other words, falsely claiming that if one event occurs, than it is safe to assume that another event would occur. However what makes it a fallacy, is that the original supposer cannot predict with certainty that the event will in fact happen, and trying to disguise the theory as fact, simply makes the argument fallatic. So what's the difference between the two? Well a double effect is a scientific generalization probability based on logical hypothesis, where as slippery slope is based on personal assertions and estimations. The underlying difference, is the fact that one cannot prove a slippery slope, where as a double effect very easily can be proven. Argument 2: Ectopic pregnancies irrelevant Now I am not completely sure I understand the opposition on this one, however I will do by best to prove how this example doesn't relate to the slippery slope opening up a double effect. When it comes to removing the felopian tube, in order to save the woman, it is not always neccesary, as my opponent suggests. While there is always a potential risk in ectopic pregnancies, having and resuming a pregnancy is perfectly possible. So when it comes to the issue of arguments for pro-lifers, a slippery slope or a double is irrelevant. But let's give the debate the benefit of the doubt, and assume a scenario where removal is completely neccesary in order to save the mothers life. Pro-lifers cannot make a slippery slope argument, or a double effect argument, because the surgery being neccesary would mean that both the mother and the childs life are in danger. So removal of the tubes being a must, would mean that pro-lifers would have to value between saving one life, or allowing both to die. This makes my opponents example completely null and void, as the purpose of the double effect argument in this case would be to prove hypocrisy in a pro life argument. But if the situation is completely un-avoidable scientifically (as I provided in my definition), then the argument is far from a slippery slope. It's a known result that will occur from the pre-supposed action. To conclude, the best way to sum up the arguments I made, is for someone to understand the difference between a slippery slope and a double effect. The two are very different, and examples such as the one Pro provided do not apply logically when trying to compare the two.