this picture will never not be funny
just the absurdity of donald duck putting out that statement (which even makes some sense and fits donald’s overall depressed mood) and mickey mouse being the sly one and contradicting donald, coming out with the upper hand from the argument, is just so amusing.
i think what donald is referring here is the concept of the universal, which is a very important concept throughout all of humanity’s history. it says that there are ever-lasting, always-present laws (the so called universal laws) that everything is derived of. As such, there are clear ways to act and that distinguish right from wrong. This is the basis of all morality and therefore also of the legal code, politics, philosophy, and everything that guides our societies.
This is also frequently brought into connection with natural law, which states basically the same thing.
The reason why it is important is because it is really the only thing holding society together. You can’t have a country of a billion people if the people think that you can just make your own laws and do whatever you want. The reason why world-spanning connections exist is because we believe in coherency, i.e. that things are the same way, more or less, everywhere, and it is therefore possible to establish communication and provide something like a connectivity tissue across the whole globe. Without that, you wouldn’t really have one humanity at all but a whole lot of very small tribes all probably fighting each other, no state building or higher society. So it’s a really important concept to think of.