War

My question is whether or not my disagreement to the next statement makes sense, and what you philosophers think about my argument. There is a popular belief that if aliens were to "visit" us, it would be in a destructive and war-like manner. I disagree. In order for a civilization to evolve and grow to one capable of interstellar travel, it would have to be a culture strong enough and intelligent enough to grow into and support such an advanced race. - If a civilization had the mindset of destroying something like a planet and every intelligent being on it, its society could not develop into something so great as to travel among the stars. - On the other hand, war has given our world many technological advancements in the past. Does this thought process make sense, what are your thoughts concerning my thinking?

Well, not really a philosophical question, but no, I don't agree withyour reasoning. I think there is little evidence for your claim that"If a civilization had the mindset of destroying something like aplanetand every intelligent being on it, its society could not develop intosomething so great as to travel among the stars." We know of only onecivilization, ours, and the claim's very nearly false for it: we almost have the ability to travel among the stars and we have alsoshown ourselves—through war, the development of nuclear weapons, andour depredation of the earth's resources—to be just about ready to destroy,either in a flash or gradually, our own planet. Prospects for ourhumane and rational treatment of other planets are not favorable.
War

Would it ever be possible to achieve world peace? The only way that seems possible is to get everyone to believe the same thing. The only way that seems possible is if there were divine interference. Since this is highly unlikely how could there ever be world peace? ~Jordan~

I suppose another way you could try to get everyone to believe the same thing is coercion, terror, and force, either outright or threatened. Doesn't sound appealing. So maybe we should rethink what's needed for world peace. Instead of thinking that it requires universal agreement, perhaps we should explore the possibility that it requires only respect for reasonable differences of opinion; instead of everyone's having the same beliefs, we need to work out a way in which sharp differences needn't lead to conflict. (You might reflect on our own society, in the U.S., which is domestically at peace and yet whose citizens have sharply conflicting beliefs about matters of great importance to them.) In this connection, you might be interested in reading Immanuel Kant's Perpetual Peace (1795) or John Rawls' The Law of Peoples (1999).

How can we rationalise societal condoned killing like war and execution. Is our collective conscience so bereft of compassion that killing others in the cold light of day is ok, especially if our peers say it is?

I'm not sure those who hold that is is just to kill or execute people under certain circumstances believe this simply because "our peers say it is". That might explain why some people have formed this judgment, but it doesn't tell us why we ought to form the judgment, that is, tell us what's to be said in the judgment's defense. (See Question 367 for more on why this would be a problematic argument.) If you think it's wrong, it's worth trying to say why it's wrong. To begin with, you might try to get a sense of the contours of your moral judgments? For instance, do you think we're also "bereft of compassion" to deprive individuals of their freedom? For the remainder of their lives? For five years? Perhaps you'd be interested in Debating the Death Penalty , a collection of essays arguing both sides of the case.