As an online discussion grows longer, the probability of a comparison involving Nazis or Hitler approaches 1.
— Godwin's Law (as cited by Wikipedia)
I have seen online, on a number of occasions, people using the above observation as some way of refuting or diminishing any argument that mentions Nazis or Hitler. Someone recently told me on Quora that my comparison suffers from being "Hitler fallacy".
Here is my response:
Why is it a fallacy?
For example, when Bush was asked: "How did you decide that torture was moral?", he answered: "I asked my lawyers, and they told me it was not illegal."
The best way to show through an example that such reasoning is wrong is to evoke the history of Nazis: everything they did was also legal, according to the laws of their democratically elected government.
Why is that logically wrong?
It's one thing if someone says that "Bush is like Hitler because...". Clearly, that's very silly, because he is nothing like Hitler, at least in quantity. But there is nothing wrong with saying that "Bush committed the same mistake as Hitler by thinking that legal equals moral", or, better yet, "We can see that Bush's reasoning is wrong by applying it to Nazis".
In my opinion, constant appeal to Godwin's Law is quite ridiculous. There is nothing logically wrong with using Nazis as a counter-example in morality or law. The episode of Nazism, WWII, Holocaust, Nuremberg trials (where people were tried by an international community for following their country's law and their superiors' orders), etc., is such a stark point in the recent history that not drawing lessons from it would be foolish.
Of course, one can also say: "Keeping slaves in the South was also legal, while helping them escape was illegal in both North and South", but I don't think it resonates quite so much. Maybe if I was Black and not Jewish, it would.
One critique one may offer is that comparing some act or thought to something Hitler did or thought is not in and of itself an argument for its immorality. For instance, saying that wearing shorts is immoral because Hitler wore them is clearly silly. But I would think it was self-evident that genocide is immoral. Of course, one does not need to bring Hitler as an example. But, when making an argument, one uses the most effective ammunition possible. Sure, I can say, "in a country where genocide is legal, you have an example of something that is legal and yet immoral". But that's is much less powerful than saying: "Under the Nazi regime, hiding Jews was illegal, while killing them was legal".
So, henceforth I am drawing CrawlingAxe's Law:
Someone who uses Godwin's Law indiscriminately clearly doesn't understand the difference between reduction and an analogy. If I say that A is like B in aspect X, I am not saying that A is the same as B in all aspects.