Honestly, the most correct thing to do with such a student is to beat him with a stick and forcibly take the money back from him (or in the less preferable case, call the police). When he cries and complains, tell him that emotional manipulation doesn’t work on you.

A. Why is it forbidden to harm another person? And what if that other person harmed me first?
B. Your second answer is exactly what people do to make others not steal, but it won’t teach him anything; it will only deter him. Next time he’ll know to steal without getting caught, and then there won’t be any painful side effects.
By the way, there are thieves whom we praise. I’m talking about people who break into other people’s homes and steal documents from them, and then the prime minister presents the loot publicly. That’s called the Iranian nuclear archive. So what’s going on here?

A. I didn’t understand the question. It is forbidden to harm another person because it is immoral. What kind of explanation are you expecting? Why is it forbidden to murder him? Or to cause him suffering? Why is anything forbidden at all (after all, that student claimed he is moral)? That is exactly why I wrote that he has to give his own definition of morality, and then we can try to discuss it.
B. You didn’t understand. This is an entirely substantive answer. If he thinks what I did was wrong, then I have nothing to say to him. And if he understands that it was wrong, then that is the answer.
You are mixing questions of different kinds. The topic is the principled justification for morality and the definitions of moral directives. You are bringing in questions of dilemma cases or borderline cases, and that is irrelevant to the matter.
The nuclear question is unrelated, and I’m surprised you don’t understand that on your own. If people are threatening to kill me, then of course I am permitted—and it is right—to steal from them in order to defend myself. What kind of question is that? And if someone harmed me first, why would I be forbidden to retaliate? That is a completely different specific question. Sometimes it may be permitted, but that is another discussion.
The fact that theft is forbidden

That’s a very good question!
Apparently there is no real answer that would obligate the student to return the money. He can say that he doesn’t have those feelings of bothering other people. There’s nothing that obligates him apart from the Torah.
If you see another possibility, enlighten me.

I understand what you’re saying, Rabbi, believe me.
I want to ask for a moment: how does the give-and-take work over what is moral and what is not? Suppose there are vegetarians who claim that anyone who eats meat is immoral. Why exactly is he immoral? After all, he harms poor animals, he separates a calf from its mother, and you can plainly see the suffering this causes her. On the other hand, there are people who do eat meat and they claim that they are very moral. So my question, Rabbi, is: according to the vegetarians, why am I not moral, and according to meat-eaters, why am I moral?

You keep mixing things up. Did you read what I wrote?

I read it and still didn’t get any good answer for the student as to why not to steal. The words “it is forbidden to steal because that’s what someone decided,” or because that’s what Kant decided, or because that’s what the law says, or because it’s simply immoral to steal—none of that convinces me at all. I want to stop stealing on condition that they show me why taking 100 shekels from so-and-so’s pocket is not okay.

You know what, Rabbi, I take back everything I said. The question is: “Who gets to determine moral values?”

There are dozens of “methods” for this. The truth is, none of them can really obligate you to obey moral laws unless you say there is some spiritual thing here, some spiritual entity that obligates us.

If you read it, then apparently you didn’t understand.

It is forbidden to harm another person because it is immoral. That’s what you said in your answer. And I want to ask: why?

And I asked: what counts as moral in your view (the student’s)? Once you explain that to me, we can try to discuss it. I’m done here.

The student says about himself that he volunteers in the community, helps the needy, participates in everything connected to social involvement; from his perspective, that’s moral.

No. That doesn’t mean he is moral. It means he does good deeds. But he does them just because he feels like it. The question is what he considers moral and binding, not what he does or doesn’t do. In other words: is there an obligation to volunteer in the community and help the needy? Why?

Rabbi Michi, can you answer clearly what is considered moral and what is not, and how this “morality” is supposed to obligate me??
I already asked you once and you didn’t answer me.

The question is too general. Can you answer me clearly what is considered beautiful and what is not, and why I should agree to it?

What is considered beautiful or not is subject to the judgment of the individual person. What is considered “moral” or not is supposed to obligate every human being as such, and therefore there ought to be some rules and definitions for it, and those rules are supposed to obligate me.
Since childhood until now I keep hearing this word “moral” all the time. This is moral and that is not moral, and in the name of that word they obligate me to behave in a certain way. So I long to know one simple thing: what are the rules of this “morality”? What or who determines what is moral and what is not? And how is it supposed to obligate me?

This question doesn’t have to be complicated, because morality is a basic thing according to which we presume to behave, and they drum it into us from kindergarten on, but somehow I still haven’t found an answer to this very basic and simple question. What is morality and how does it obligate me?

I wasn’t comparing aesthetics to ethics; I was trying to illustrate for you how general your question is and why it can’t be answered that way.
I assume that you understand exactly as I do, and as every other person does, what morality is and what it obligates (except for certain cases where there may be room for hesitation), and therefore I see no need to spell it out. If you do not understand, then no amount of detail will help.
As for the basis of the validity of morality, in my opinion the obligation of morality stems from the fact that this is God’s will. See column 456.
And I’ll conclude with a methodological remark: the fact that this is a basic question does not mean it is simple, and certainly does not mean it can be answered in one message in a thread like this. The four fundamental forces of physics are the most basic forces there are. But in order to understand them one has to study for many years.

1. I admit that I understand what morality is, but only in a few general things, like not hurting another person, doing good, and a few other general things, because for that there is conscience (I’m not sure that if I had been born into an environment where killing was permitted I wouldn’t think it was justified). But beyond that I really don’t know what is moral and what is not, starting from gender separation, pornography, abortion, euthanasia, and many other controversial issues.
2. And likewise in many complex situations that a person encounters in everyday life, this very general definition of “morality” doesn’t know how to adapt itself to a situation that is even a little complicated and has some complexity.
3. The fact is that so many sectors, peoples, religions, and opposing opinions struggle over many things, and each one swears that it is the moral one and the other is not.
Likewise, there are things that were considered immoral a hundred years ago and now they are a consensus, and vice versa. All this says something about the strength and stability of morality.
4. I can rely on my intuition, on my upbringing, on what I feel, on what most people do—but that doesn’t determine whether something is “moral” or not. Or does it?

If so, then the question now changes completely. What you actually want is for me to list all the borderline cases and explain regarding each one what is moral and what is not. Are you serious? Is that the answer you’re waiting for? If you have a concrete question, by all means raise it, and also write what the sides of the dilemma are. You are being lazy and tossing out general slogans with a partial list of topics that in your opinion are vague. By contrast, you expect from me a comprehensive treatise with a systematic and orderly solution to all the problems, and all that in an internet message.
As a rule, it is not true that there are so many disputes. There are disputes at the margins, and usually they are not substantive but based on different interpretations of the same principles.
The fact that there is moral progress only confirms that there is valid morality, and thank God we are usually getting closer to it (not always, of course). Physics also changes all the time, and what people once thought they no longer think today. So does that mean there is no correct physics either? Or perhaps you want a comprehensive course in physics here?
In principle, a person is supposed to rely on his intuition. That is the tool we have. But it is worthwhile to listen openly to other views and arguments and reconsider.

“There is moral progress” — later on, when we forcibly inject viruses and pieces of mRNA code into human beings, and throw the unvaccinated into ditches, that will certainly be, in your eyes, the height of morality.

Honorable Rabbi, I think there’s been a mistake here. You are not “obligated” to do anything, and I’m not expecting anything from you; as far as I’m concerned, you can be as arrogant and condescending as you like, and that’s perfectly fine.
I thought morality was supposed to have some basic rules and definitions, but if you say it doesn’t, then it doesn’t. I’m only wondering whether I too can from now on “nationalize” the word “moral” and use it however I want, just like schoolteachers, TV broadcasters, and rabbis use it.