> like the study of economics [...] There are no universal laws that always hold true in all situations
I've got great news for you! There are universal economic laws that always hold true in all situations.
For example, "man acts". You can't deny that, because denying it would be an act in itself, leading to a (performative) contradiction. From this law, and just a few others of a similar kind, you can build a whole structure of logically provable theorems that have profound implications for economics and the social sciences in general.
Is this satire? I'm sorry, I legitimately cannot tell anymore.
Anyway, if it isn't -- no, there are no universal economic laws, for the very simple reason that "humans are not always rational" and economics is fundamentally about human behavior, in groups, no less.
Predictable only insofar as it has to follow some simple rules. For example, if you own a good G, that you could use to satisfy either a desire D1, or a competing desire D2, you will choose to use G to satisfy the greater one of these two desires at that point in time.
Repeatable is even untrue, unless I misunderstand your meaning. First of all, the ranking of your goals or desires is not assumed to be constant over time. Also, it is not assumed that your world model is constant. Quite the opposite, it is often explicitly emphasized that humans have the ability to change their mind about things, for example by learning.
The law of diminishing marginal utility for example can be logically proven using this method. Alas, knowing it won't make you rich, the world is not that simple.
> the more of something you have, the less of it you want. This phenomenon is referred to as diminishing marginal utility by economists.
Okay, but I have a counter-example. Money. The people who have the most sometimes still act like penny-pinchers, and lust after even more, and haggle over the smallest things. Therefore the "law of diminishing marginal utility" is more a rule of thumb than a law.
Um, there's not a whole lot of economic laws that are less controversial than the law of diminishing marginal utility. I'll give you a rough outline.
If you own a good G, that you could use to satisfy either a desire D1, or a competing desire D2, you will logically choose to use G to satisfy the greater one of these two desires - the one with the greater subjective utility to you. Let's assume that is D1.
Now, if instead of 1 you have 2 of G, you can satisfy both D1 and D2. As we have already established that the utility you have derived from consuming the first G to achieve D1 must be greater than the utility derived from consuming the second G to achieve D2, the utility of the additional unit of G is diminished when compared to the previous one.
Your counterexample isn't one. It's a made-up, incoherent mess, that doesn't show in any way what you claim it does. That starts with the incomplete definition of the law itself, which is part of a single sentence that you pasted off a multi-page Wikipedia article on the topic, which isn't exactly the best source in the first place. Why don't you just try to think through the simple explanatory outline I gave you?
Agree with sibling comment that this is more "heuristic" than "law". There are many things that have basically 0 utility up until some threshold, there are things that become more marginally useful the more of them you have (users for your social media app)
You take 1000 economists and ask them for opinions on a certain problems, you will get hundreds if not thousand different solutions. If you do math say a million mathematicians/physicists, you will almost always get a few if not 1 solution to the problem. By the way, Nobel for economics isnt even part of original Nobel. It basically force fed into it and tag with Nobel label. Economics is essentially just common sense applicable at the specific time...at other times it will fail.
Since OP didn't provide any, I looked up some sources for the "man acts" economic axiom.
I found https://en.wikipedia.org/wiki/Praxeology, which is used by the so called Austrian Economic school.
Actually the axiom is "man acts purposefully". There is also quite some criticism on it, which can be found on the wiki page as well.
I've got great news for you! There are universal economic laws that always hold true in all situations.
For example, "man acts". You can't deny that, because denying it would be an act in itself, leading to a (performative) contradiction. From this law, and just a few others of a similar kind, you can build a whole structure of logically provable theorems that have profound implications for economics and the social sciences in general.