In war memoirs, there is sometimes talk about a feeling of invulnerability among soldiers new to combat: it never occurs to many people that they themselves might be killed. But then something punctures the feeling: it might be that a friend dies, or it might be the sheer quantity or awfulness of death, but at that point the recruit "sees the elephant" and gains a sense of their own mortality. Well, if someone "sees the elephant", how would philosophers characterise the change in epistemological status? For instance, would it be fair to say that the person has gained new knowledge, ie now knows that they're mortal, whereas they didn't know this before? Or is just a case of probability weightings of possible outcomes having changed in the light of new data?

It's a fascinating question. When the recruit "sees the elephant," as you put it, they seem to gain something that calls out for an epistemological characterization, but just what they gain is harder to say. The problem is that the obvious suggestions don't seem to work. The recruit already that s/he is mortal. Likewise, his or her probabilities haven't shifted. The recruit presumably already thought that death is certain. So what might the recruit have gained if not knowledge or improved probability judgments? One answer is salience. It's one thing to know something; it's another for it to figure significantly in your outlook. If something is salient for me, it plays a different role in guiding my actions than it does for someone who knows it's true but gives it little thought. On one model, our actions are guided by probabilities and judgments of importance or value/disvalue. But not everything that we know or believe plays a role in our decision-making, and likewise not everything we see as good or...

In America, many people join the military as a means to socio-economic advancement (e.g. in order to pay for college). Is this ethically defensible? Is there any difference between someone who enlists for career advancement and a mercenary?

Consider two people who join the military. Person A's motive is socio-economic advancement. Joining the military seems the best path to a good career. But s/he also accepts the country's values, thinks the country needs a military, and thinks that being in the military is an honorable profession. S/he would not join the military of any other country that might possibly be unfriendly to her/his own country. Person A's motive is likewise socio-economic advancement. S/he doesn't care about the country's values, is not interested in the question of whether the country should or shouldn't have a military, and doesn't care about whether being in the military is honorable. S/he would join the military of any country whatever provided it was advantageous enough to do so. I believe that there are many people who join the military whose reasons are like Person A's. But I think there's a pretty clear moral difference between the motives of A and B. Now of course there are also people who join the military...

Excluding people drafted, isn't a soldiers life less important than a civilians. Otherwise what is the point of protecting them. A good mother would give her life to protect her child because the child's life holds more value right? Or am I misunderstanding why one sacrifices ones self.also if a person joins the military but isn't willing to go through whatever (torture, death etc..)is required doesn't that make them cowards or even something worse.

I think we can begin with this premise: a soldier's life is every bit as important as a civilian's. The fact that soldiers volunteer to protect civilians doesn't give us any reason to believe otherwise. Many soldiers believe that serving their country is a higher cause, and worth sacrificing their lives for if that's what circumstances demand. That's not a judgment about the comparative value of their own lives compared with the lives of the civilians they save. In fact, it's perfectly consistent for someone to think that any able-bodied citizen should be willing to sacrifice his or her life for the good of the country, if that's what's called for. Good parents may well be willing to give their lives for the sake of their children. But that's not a judgment about whose life is worth more. Related but not the same: Mary may be willing to die to save her child. She might not be willing to die to save a stranger's child. But that doesn't mean she thinks her children are more valuable than children...

The artists, writers and poets who witnessed World War I aside, why is there such an aversion to chemical weapons? Don't 'conventional' weapons kill people just as dead? Are chemical weapons more inherently immoral than conventional weapons?

I don't know much about weapons of war, so I can't be confident of the details here, but consider this thought. Suppose an army has a choice between two kinds of weapons. The two are equally lethal, but one kills quickly while the other leads to a slow, painful death. That seems to be a good moral reason for using the first rather than the second. The enemy soldiers will be just as dead, to use your phrase, but the world will have been spared some suffering. The chemical weapons that those World War I poets wrote about—mustard gas, for example—were so horrifying precisely because they killed so slowly and so painfully. I take it that's the reason (or at least one reason) for treating chemical weapons differently from bombs and guns. And on the face of it, it seems like a pretty good one.