When approaching decisions, we tend to wonder what will work. Is the plan I'm considering effective? Will it work? Is the outcome positive? We weigh the various risks, rewards, costs, and benefits. We compare advantages and disadvantages. We throw all of our intellect at the problem.
There's a more important question than "Will it work?" That question is "Is it what God wants?" Is this decision in line with God's will? Is it perhaps against God's will? These questions are far more important than determining if something is effective. In fact, it really doesn't matter if something is effective if it is opposed to God's will. And it doesn't matter if it is going to be entirely ineffective, if it is God's will.
Abortion is actually very effective at its goal. I'd say its effectiveness rating is very, very high. It clearly accomplishes what it intends a high percentage of the time. Abortion = effective. Is that the most relevant criteria here? Is it in God's will?
The effectiveness of torture is up for debate. It may or may not work as well as some people say. And we can also debate how likely it is we'll have the chance to torture a terrorist as the only means by which we could save a city from certain destruction. We do debate this a lot though. I think they've had whole hearings on it. I won't make a claim on its effectiveness, because I don't believe that's the first question we should ask. Is it God's will?
On the flip side, prayer doesn't seem very effective when we think about it. Does me asking God to help you actually help you in some sort of measurable way? I'm a process engineer. I frequently will only call things effective if I can measure them. Does my church here praying for aid to some other country actually bring about some sort of change in the other country? If I pray another might find God and they don't, doesn't that mean prayer is ineffective? Again, there are a lot of thoughts on this one. I've asked a priest this and I've looked online and I've tried to figure it out. In the end though, it doesn't really matter. The important question is if it is God's will.
Does giving money to the poor guy on the corner allow him to eat or are we just enabling his drug habit? What is God's will for us in that moment?
Is downloading music I haven't purchased an effective method of expanding my music collection? Does it matter? What is God's will for me?
Will selling everything I own and becoming a missionary give me a more effective life? Is God sending me? (No, I don't think He is at this point - this is just an example).
We ask our questions in the wrong order. God's will is the only thing that matters. If the decision is morally neutral, then of course we can use our God-gifted reason to come to a conclusion. But we must always examine the moral aspect first.