I really cannot bear an immoral man. I am not a Pharisee, I hope; and I should not have minded his merely doing wrong things: we are none of us perfect. But your father didn't exactly do wrong things: he said them and thought them: that was what was so dreadful. He really had a sort of religion of wrongness. Just as one doesn't mind men practising immorality so long as they own that they are in the wrong by preaching morality; so I couldn't forgive Andrew for preaching immorality while he practised morality. You would all have grown up without principles, without any knowledge of right and wrong, if he had been in the house. You know, my dear, your father was a very attractive man in some ways. Children did not dislike him; and he took advantage of it to put the wickedest ideas into their heads, and make them quite unmanageable. I did not dislike him myself: very far from it; but nothing can bridge over moral disagreement. (1.67)
Lady B lets us know right off the bat that she has a very firm sense of right and wrong, and it runs directly counter to her husband's. Her children seem to share her views that Andrew Undershaft is a thoroughly immoral man—for now.
LOMAX [to Barbara, still rather shocked]: Yes; but what about the cannon business, don't you know? [To Undershaft]: Getting into heaven is not exactly in your line, is it? LADY BRITOMART: Charles!!! LOMAX: Well; but it stands to reason, don't it? The cannon business may be necessary and all that: we can't get on without cannons; but it isn't right, you know. On the other hand, there may be a certain amount of tosh about the Salvation Army—I belong to the Established Church myself—but still you can't deny that it's religion; and you can't go against religion, can you? At least unless you're downright immoral, don't you know. (1.206-208)
It seems that Charles Lomax is definitely hopping on the bandwagon with the opinion that Undershaft is immoral, pointing to Andy's profession and how it "goes against religion" as evidence. He admits that he thinks cannons are necessary, but they still aren't "right." Hmm, that seems like a bit of a contradiction, doesn't it?
Not at all. The more destructive war becomes the more fascinating we find it. No, Mr. Lomax, I am obliged to you for making the usual excuse for my trade; but I am not ashamed of it. I am not one of those men who keep their morals and their business in watertight compartments. All the spare money my trade rivals spend on hospitals, cathedrals and other receptacles for conscience money, I devote to experiments and researches in improved methods of destroying life and property. I have always done so; and I always shall. Therefore your Christmas card moralities of peace on earth and goodwill among men are of no use to me. Your Christianity, which enjoins you to resist not evil, and to turn the other cheek, would make me a bankrupt. My morality—my religion—must have a place for cannons and torpedoes in it. (1.213)
In response to Charles's "excuse" for his immoral profession, Undershaft says he refuses to be ashamed or hypocritical about it. Apparently, some of his peers try to redeem themselves by making a display of using their profits to donate to humanitarian causes (indicating some level of shame or contrition for how they make their money)…Well, Andy doesn't play that way. He puts profits back into his business, refusing to make apologetic gestures for something he doesn't find to be wrong.
STEPHEN [coldly--almost sullenly]: You speak as if there were half a dozen moralities and religions to choose from, instead of one true morality and one true religion. UNDERSHAFT: For me there is only one true morality; but it might not fit you, as you do not manufacture aerial battleships. There is only one true morality for every man; but every man has not the same true morality. (1.214-215)
When Stephen presses Undershaft on his moral relativism, Undershaft rejects the notion that you can just randomly pick a religion or moral system; rather, your life circumstances define your moral compass/religious path. Do you agree?
It's quite simple. As Euripides says, one man's meat is another man's poison morally as well as physically. (1.217)
When Charles Lomax is completely baffled by Andrew's answer about individual moralities and religions, this is how Dolly tries to explain it. Basically, he's saying that different things nourish different people (spiritually, that is); different strokes for different folks.
It would be most unnatural and improper of you to leave it to anyone else, Andrew. Do you suppose this wicked and immoral tradition can be kept up for ever? Do you pretend that Stephen could not carry on the foundry just as well as all the other sons of the big business houses? (3.70)
Lady B's big problem with Andrew is not really his line of work—when she talks about the immorality that broke them up, she really means Andrew's decision to leave the business to a foundling, as his family's traditions dictate, instead of to their son, Stephen.
Look at poor little Jenny Hill, the Salvation lassie! she would think you were laughing at her if you asked her to stand up in the street and teach grammar or geography or mathematics or even drawing room dancing; but it never occurs to her to doubt that she can teach morals and religion. You are all alike, you respectable people. You can't tell me the bursting strain of a ten-inch gun, which is a very simple matter; but you all think you can tell me the bursting strain of a man under temptation. You daren't handle high explosives; but you're all ready to handle honesty and truth and justice and the whole duty of man, and kill one another at that game. What a country! what a world! (3.125)
Andrew gets animated during a chat with Lady B and Stephen about what Stephen is supposed to do with his life if he doesn't take over the family business. As usual, Andrew is pretty cutting with his logic, suggesting that it's a bit weird that people resist claiming knowledge or expertise in all kinds of areas, but they think nothing of claiming to be authorities on morality. Who ever put them in charge?
My good Machiavelli, I shall certainly write something up on the wall; only, as I shall write it in Greek, you won't be able to read it. But as to your Armorer's faith, if I take my neck out of the noose of my own morality I am not going to put it into the noose of yours. I shall sell cannons to whom I please and refuse them to whom I please. So there! (3.294)
Discussing the various mottos that generations of Undershafts had put up on the factory wall, Dolly plans his own—and tries to set out the terms of his own morality, rather than taking on Undershaft's as his own.
I will take an order from a good man as cheerfully as from a bad one. If you good people prefer preaching and shirking to buying my weapons and fighting the rascals, don't blame me. I can make cannons: I cannot make courage and conviction. Bah! you tire me, Euripides, with your morality mongering. (3.302)
Undershaft refuses to take moral responsibility for any evil (or good) that his cannons do—as far as he's concerned, he's just obligated to make the cannons available so that both sides can duke it out. He refuses to determine who "deserves" the cannons and who doesn't. How…fair…of him.
Come, come, my daughter! don't make too much of your little tinpot tragedy. What do we do here when we spend years of work and thought and thousands of pounds of solid cash on a new gun or an aerial battleship that turns out just a hairsbreadth wrong after all? Scrap it. Scrap it without wasting another hour or another pound on it. Well, you have made for yourself something that you call a morality or a religion or what not. It doesn't fit the facts. Well, scrap it. Scrap it and get one that does fit. That is what is wrong with the world at present. It scraps its obsolete steam engines and dynamos; but it won't scrap its old prejudices and its old moralities and its old religions and its old political constitutions. What's the result? In machinery it does very well; but in morals and religion and politics it is working at a loss that brings it nearer bankruptcy every year. Don't persist in that folly. If your old religion broke down yesterday, get a newer and a better one for tomorrow. (3.306)
Here we get more of Undershaft's life philosophy, which is utilitarian as ever—in his view, if a morality doesn't suit your needs, you gotta chuck it. Obviously, this view is hard for Barbara to swallow, since she had gone all in on the picture of morality and religion that the Salvation Army presented to her . . . she definitely needs more convincing.