Probably most everyone has read Dulce et Decorum Est by Wilfrid Owen. I read it in a poetry anthology my parents gave me when I was junior high age. It's a gripping poem describing the horrors of war (Wilfred Owen was a soldier in World War I, the "war to end all wars", in which he ended up dying) and it ends:
My friend, you would not tell with such high zest
To children ardent for some desperate glory,
The old Lie: Dulce et decorum est
Pro patria mori.
There is no questioning the truth in the experience he recounts; it is I think a blazing corrective to facile jingoism, especially the kind that plays fast and loose with young generous lives. War is certainly ugly enough that we should not rush into it without just cause.
CS Lewis was a World War I veteran too. He was wounded, and two of his buddies killed, in that war. One of them was "Paddy" Moore, who had asked Lewis to care for his mother in the event of his death, a commission Lewis carried out conscientiously, to the point of caring for her as his own mother until she died.
It was much later (in 1943) that Lewis wrote Abolition of Man, in which he uses the same tag from the ode by Horace as what he calls the experimentum crucis of the case:
He's certainly chosen a good example to test differences in systems of thought. "Greater love hath no man..." seems easier because most of us, no matter how we were brought up, can imagine circumstances in which we would die to save someone else. Even Gaius and Titius, the writers of the Green Book, might risk themselves a little bit for the sake of a true affection, even if against their calmer judgment.
Let us continue to use the previous example—that of death for a good cause—not, of course, because virtue is the only value or martyrdom the only virtue, but because this is the experimentum crucis which shows different systems of thought in the clearest light. Let us suppose that an Innovator in values regards dulce et decorum and greater love hath no man as mere irrational sentiments which are to be stripped off in order that we may get down to the 'realistic' or 'basic' ground of this value. Where will he find such a ground?
I think the dulce et decorum bit is a little more difficult, perhaps, because it's usually a case of a country sending out its young men to fight for that country. Here trust and gratitude are implied as well as love and loyalty -- trust in the country that is sending you out; trust that your efforts and possible death will mean something to that country; gratitude for the country that has given you a place to stand. You are dedicating yourself to the ideal of honour.
CS Lewis has a footnote in this chapter in which he allows himself an acerbic conclusion to a rather detached though telling list of the Innovators', Gaius's and Titius's, "approvals" and "disapprovals".
Disapprovals: A mother's appeal to a child to be 'brave' is 'nonsense' (Green Book, p. 62). The reference of the word 'gentleman' is 'extremely vague' (ibid.) 'To call a man a coward tells us really nothing about what he does' (p. 64). Feelings about a country or empire are feelings 'about nothing in particular' (p. 77).You can hardly blame him for that note of acerbity considering his own war-time experience and that of his friends and peers (the UK casualty rate was horrendous; hardly a family was left untouched). Lewis was not talking from an ivory tower when he brought up death for one's country as the test case for a moral system.
Approvals: Those who prefer the arts of peace to the arts of war (it is not said in what circumstances) are such that 'we may want to call them wise men' (p. 65). The pupil is expected 'to believe in a democratic community life' (p. 67). 'Contact with the ideas of other people is, as we know, healthy' (p. 86). The reason for bathrooms ('that people are healthier and pleasanter to meet when they are clean') is 'too obvious to need mentioning' (p. 142). It will be seen that comfort and security, as known to a suburban street in peace-time, are the ultimate values: those things which can alone produce or spiritualize comfort and security are mocked. Man lives by bread alone, and the ultimate source of bread is the baker's van: peace matters more than honour and can be preserved by jeering at colonels and reading newspapers.
Who was it, after all, that had helped ensure that Gaius and Titius could continue to earn their bakery bread writing textbooks which smugly dismissed such things as bravery and honour as mere sentiment to be debunked? Who had been wounded himself, and seen others die, and then had to read that such things were "nonsense" and "about nothing in particular"?
You can see echoes of this same dichotomy in Charlotte Mason's introduction to her last book Philosophy of Education, written shortly after World War I (1922). Mason writes:
These are anxious days for all who are engaged in education. We rejoiced in the fortitude, valour and devotion shown by our men in the War and recognize that these things are due to the Schools as well as to the fact that England still breeds "very valiant creatures."
.... But what about the abysmal ignorance shown in the wrong thinking of many of the men who stayed at home? Are we to blame? I suppose most of us feel that we are: for these men are educated as we choose to understand education, that is, they can read and write, think perversely, and follow an argument, though they are unable to detect a fallacy. If we ask in perplexity, why do so many men and women seem incapable of generous impulse, of reasoned patriotism, of seeing beyond the circle of their own interests, is not the answer, that men are enabled for such things by education? These are the marks of educated persons; and when millions of men who should be the backbone of the country seem to be dead to public claims, we have to ask,––Why then are not these persons educated, and what have we given them in lieu of education?
I am not in the military service myself, but I imagine that the reason that soldiers go to fight, suffer and perhaps die is not so much that they long to preserve the steady arrival of bakery vans to suburbs, nor leisure for suburbanites to pronounce smug platitudes about peace and tolerance; rather, that they want to protect things that are precious and yet immaterial, things like freedom and happiness for their mothers and siblings and wives and children, aid to the weak, honor for their nation, so that it doesn't have to kowtow to tyranny.
In other words, precisely the intangibles that men like Gaius and Titius scoff at and debunk for the sake of "realism".
I would take it that when the Roman statesman told his son that it was sweet and seemly to die for his country, he was speaking for himself as well; it was something he would have done himself when he was younger, and he was willing to risk his own progeny to preserve the fatherland. As CS Lewis pointed out, he was telling his son what he believed to be the truth.
After all, if everyone dies (the ancients were more in touch with their mortality than modern suburbanites are) then how you die is what matters in the end. This is something Gaius and Titius probably would not understand.
When Gaius and Titius dismiss all those things as meaningless nonsense, they leave themselves and their country only two alternatives. If they can get everyone else to agree with them, the days of suburbs and timely bakery vans will be numbered, and they will have to learn to be smug organs of whatever tyrannous state results, whether sooner or later. Their death, when it comes, will be a craven and ignominious one, honor and courage traded off for a false peace.
If they realize that their pragmatism is fatal for the survival of their state of life, they are going to have to do something even worse -- brainwash the children in their schools to do something that they would never risk doing themselves, something they believe is "nonsense", though convenient for their country and those that stay at home. They will have to restore some version of Dulce et Decorum, but it will be manipulative propaganda. Their death when it comes will be the death of traitors and exploiters of the young.
(I can think of a third possible alternative -- the path of a conscientious pacifist. I am leaving that option entirely out of this because this path draws from an appeal to conscience and tradition that Gaius and Titius would think just as nonsensical as the Roman one... they are realists, after all.)
Whether or not I ever have a son who joins the military service, I hope to raise children who realize that these two "realistic" alternatives are no rightful alternatives at all; that when you perceive their bitter toxicity, "dulce et decorum" do not seem like such ironic adjectives anymore.