Where is it written that what is 'natural' is morally acceptable? Unless some argument is offered for this claim, there is a blatant non sequitur in these remarks.

First, I would take issue with the claim that war nowadays causes many fewer casualties. While this may be true for soldiers in the armed forces of modern industrial societies, it is clearly not so for the civilian population or even for the soldiers in "third world" nations. The Vietnam War is a good example of what I mean. But if I understand the question, I think "fair fight" is definitely not an ethical requirement, though fighting a "just war" is. To see what I mean by this distinction, consider the ethics of launching a surprise attack. Though in a clear sense this isn't "fighting fair", my view is that if the cause is just and it helps to win the war, of course do it. However, there are moral rules about how to conduct war, and, say, targeting civilians in order to reduce casualties among one's own soldiers is a violation of those rules. As long as one is fighting a just war, and conducting it justly, I don't see that the notion of fighting fair is relevant. After all, war is not a sport.

This question cannot be answered in general terms. Some killings that you may be required to perform may be justifiable, others not. Generally, killings in war are thought to be justifiable when two conditions are both fulfilled: Your country must have a just cause for being involved in the war in the first place. And each potentially lethal action within the war must be aimed at a legitimate target while taking great care to spare others who are not a threat. You must reassure yourself on both counts before you start killing people on the orders of others. This can be quite straightforward when you are ordered to defend your country against invading soldiers. But it can be far more difficult, if not impossible, when you are ordered to participate in an attack upon, and occupation of, another country.

Taking the U.S. invasion of Iraq as an example, there is considerable doubt about the first condition. The U.S. sought but failed to obtain UN Security Council authorization. The weapons of mass destruction supposedly held by Saddam Hussein's regime never turned up. There is no evidence for Hussein's alleged collaboration with Al Qaeda. Major human right violations committed by his regime were committed in the 1980's when the U.S. was actively supporting Iraq's war against Iran. Here you need to identify some cause and reassure yourself that it is sufficient to justify the attack on Iraq.

Regarding the second condition, various estimates put the number of Iraqi civilians killed as a result of the U.S. invasion at between 65,000 (Iraq Body Count) and 655,000 (the Lancet). Many were killed by local groups, to be sure, but only because the U.S. -- seeking to keep our troop commitment low -- failed to maintain public order and security. Many more were killed through indiscriminate U.S. bombardment of civilian areas from which hostile fire was supposedly received or to which suspected insurgents had supposedly retreated. Other civilians again were killed by U.S. troops taking revenge for losses suffered from roadside bombs or other attacks. (Last Saturday, 27 May 2007, for example, the Washington Post reported that: "Witnesses to the slaying of 24 Iraqi civilians by U.S. Marines in the western town of Haditha say the Americans shot men, women and children at close range in retaliation for the death of a Marine lance corporal in a roadside bombing.") If you conclude that the war is just, and decide to go to Iraq, you need to avoid being involved in the intentional or negligent killing of non-combatant civilians. If, on the basis of the evidence you have about the conduct of U.S. forces in Iraq, you anticipate that this would be very difficult or impossible to achieve, then you ought not to go in order to avoid being involved in unjustifiable killings.

It probably does, and a state of affairs in which everyone was blissfully happy would be very unproductive of anything except happiness. It is a bit like what we tend to think of as normal stress. If an individual is overwhelmed by stress, that is obviously a bad thing both for her and her work. If an individual feels no stress at all, then why should she do anything at all? We need some motivation to get going, presumably, and a degree of stress is fine to motivate us to get things done and succeed in our tasks. The thing about war, though, is that it so easily slips from being a period of some aggravation to becoming a highly destructive environment. What we need from a cultural point of view perhaps is more but much smaller wars!

We might wonder whether world peace would be so desirable. Isn't some conflict rather stimulating and exciting, and would it not be boring if everyone was in perfect harmony with everyone else? Of course, peace would be preferable to immense murder and destruction, however lacklustre it might turn out to be. On the other hand, an ideal state of affairs might be thought to include at least some conflict and aggression, and so the ideal of world peace may not be realized because few people actually want it to be realized.

There is nothing incoherent about the ideal of world peace, even when we hold fixed that human beings have conflicts and disagreements as well as greed, pride, and a desire for power. Nonetheless, world peace may be empirically highly unlikely in a system of states like the one we have been having for the last few centuries.

One might argue for this pessimistic conclusion as follows. Some people strive for power, and such people are likely to be substantially overrepresented in politics (as those who like power are more likely to go into politics and as those in politics acquire a taste for power). The domestic power of politicians tends to increase in times of tension and hostility as a frightened public is willing to cede to politicians greater authority.

The international power of politicians may be increased or decreased by heightened tension and hostility. Which it is depends on what their country's power is mainly based on. There are three main components of a country's political power: military might, economic strength, and the moral compellingness of its claims. Countries differ in the composition of their power. Thus, the US and the old USSR are/were much stronger in terms of military might than in regard to the other two components. Japan is much stronger economically than in regard to the other two components. East Timor is much stronger in moral terms than in regard to the other two components.

Now, how much each of these three components of a country's political power matters depends on the regional or global political climate. In a context of security threats, military power matters greatly. Therefore, the politicians of countries that are especially strong militarily can increase their international power by maintaining such a political climate of threatened security. The politicians of the remaining countries have the opposite interest. But then a political climate of threatened security is much more easily maintained than avoided. So, in a states system, a political climate of threatened security is likely to be maintained by the politicians of those countries whose share of international military might exceeds their share of global economic or moral strength -- because these politicians gain power, both domestically and internationally, from such a climate (whose maintenance requires occasional wars and military interventions, fear of war, and/or quasi-wars such as those on drugs, terror, and the like).

Obviously, this is a very simple, thumbnail account of politics which, no doubt, could be made a lot more sophisticated with further empirical work examining the politics of the last few centuries. If the hypothesis, or one broadly like it, holds up, then lasting world peace is highly unlikely to be achieved within a states system. And we may then have reason to seek alternative modes of organization, perhaps going in the direction of confederation on the model of the European Union. But the prospects of such a transformation may be dimmed by the very same forces that now impede world peace. Perhaps the European Union was an unlikely development, made possible by the fact that the main states involved did not differ much in the composition of their power and all benefited from joining forces (by bettering their competitive position vis-a-vis the US and USSR). No such special factors are likely to emerge globally: Great discrepancies in the composition of national political power are likely to continue, and an extra-terrestrial competitor is unlikely to materialize.

I take it that the desire for "world peace" is a desire for an absence of war. So my question to you would be: Why do you think that the fact that there will always be disagreements and conflicts means there must always be war? Surely there are other ways to resolve such disagreements. The United States has disagreements with Canada; Canada has disagreements with Japan; and so on and so forth. But they're not shooting at each other.

The real obstacles to peace, I'd have thought, are things like greed, pride, and a desire for power.

This is a really difficult question. If terrorism is the killing of civilians in order to achieve some political end, vast empires as well as fringe political groups commit terrorist acts--sometimes appealing to a state of war to justify their killings (but a declaration of war doesn't seem to make a moral difference.) If the history of terrorism by vast empires justifies terrorist acts by fringe political groups, then one would have to say that the violent measures taken by the empires (prolonged detention and torture of suspected terrorists, for example), are also justified. But if that is the case, what does 'justified' mean, and why should anyone care whether an act is 'justified'? One thought: 'justified' seems to mean at least two different things: the best thing to do, in the circumstances (which could be quite a bad thing to do, considered by itself), and 'a good thing to do' or 'the right thing to do', period. I think a terrorist act might be justified in the first sense, but not in the second, but many people condemn terrorists thinking that terrorists don't recognise the costs of their actions (to their victims), and so don't see their acts as bad by themselves and merely excusable given the circumstances. And I suppose that starting to think about this sort of complexity would paralyse many would-be agents of terrorist acts.

I'm not quite sure what you mean by 'taking into account history'.

You may mean that only violence can end oppression. This is controversial, of course: didn't Gandhi's non-violent independence movement lead to the end of British colonial power in India? And even if there aren't any historical precedents of non-violent movements ending oppression, should we assume that such a thing can never happen?

If you mean (by 'taking into account history') that vast empires got their power by acts of terror themselves, then the answer to 'is terrorism against vast empires justifiable?' may be seem to be one you could settle by figuring out who was the first aggressor. But given history, the first aggressors are often long gone, and the targets of alleged retaliations, while they may be beneficiaries of the first aggressions, aren't themselves aggressors (at least not individually). Is it right for them to be the targets of terrorist acts? Terrorist actions are always (said to be) justified in terms of the wrongs they seek to rectify; perhaps, to figure out what actions are justified (in the second sense distinguished above), we would all do better to focus on the question of how the future generations of the world can best live.

I am not sure what you mean by "an absolute pacifist." If you mean that you would not even disarm a person who was attempting to kill you, then you may have a problem reconciling it with practising a martial art. However, there does not seem to be any good nonreligious reasons to be an absolute pacifist in this sense. One can be a pacifist in a fairly absolute sense by refusing to ever seriously harm another person, and though there might be situations in which even this view would be hard to defend, it is somewhat more plausible than absolute pacifism. Another even more plausible form of pacifism is refusing ever to kill another person.

If practising a martial art does not involve practising killing anyone then it is not incompatible with the most plausible form of pacifism that I mentioned above. If practising a martial art does not involve practising seriously harming anyone, then it is not incompatible with the somewhat plausible form of pacifism that I mentioned above. I assume that practising a martial art does involve practising disarming someone who is attempting to kill you. However, I see no problem with this, as I cannot see why anyone would hold absolute pacifism in the sense I gave it.

You refer to absolute pacifism and practising a martial art as two conflicting philosophies. That seems to me to be a misuse of the term "philosophies." Although pacifism may be the result of some philosopical view, it need not be, and although practising a martial art may be prompted by acceptance of some philosophical view, it need not be. One can practise a martial art simply for the exercise, mental as well as physical and yet be committed to never using it to kill or seriously harm another person. So there need not be any conflict at all.

One of the criteria philosophers generally agree upon for just war is "legitimate authority"--that is, a just war must be authorized in legitimate (usually meaning lawful) ways. The United Nations charter and the U.S. Constitution, for example, set out procedures for properly authorizing war, as will the legal codes of most nations. To evaluate the legality of this war, one must extablish whether those procedures were followed in proper ways. In particular, here you should look at whether the U.S. Congress authorized the war and whether the U.N. Security Council authorized the war. (See Articles 39, 42, 51 of the UN Charter; also see Security Council Resolution 1441; see the U.S. Congress's Joint resolution on the war of October 2002.) Another issue to consider is whether or not, even if authorization was given, the authorization was rendered illegitimate or void since it was predicated on deceitful claims about the nature of the threat posed by Iraq. You may also consider whether any "customs," "norms," or "informal conventions" of international relations legitimate the war.