The “what if everyone did that” thing isn’t an argument. 9 times out of 10, the person using it suggests that a switch is flipped and suddenly everyone does that. That’s not the case at all. For example, say you went back seventy years when 12 hour days was the norm and told them that you worked only about 8 hours a day and they say, “Oh my! That would never work. Imagine if everyone did that, nothing would get done!” But a lot of stuff gets done now, doesn’t it?
We leverage technology to do great things in a shorter amount of time now. And let’s not forget the law of supply and demand. For example, if everyone did what they felt their purpose was and there were no garbage-collectors left, this is some of what might happen: 1. The wages for a garbage collector would skyrocket. 2. People would have to clean up after themselves. 3. There would be a greater demand for solutions that didn’t require humans or as many humans, such as automated cleaning machines, and the people who really enjoy solving society’s problems using technology would love to create that.
As another example, 100 years ago, even middle class houses had some servants. Today, however, only the uber-rich enjoy any sort of servants. Part of the reason is that human labour became too expensive for most people to afford and people managed to cope. Other solutions came from technology. For example, instead of washers we have washing machines. Instead of cleaners we have vacuum cleaners. So, I have faith in humanity’s ability to cope with most things that are a case of “what if everyone did that”, and thus 9 times out of 10 it isn’t a credible argument against anything because it is so blatantly invalid.
The “you’re wrong because I disagree with you” thing also isn’t an argument. Someone may have different values from another person but that doesn’t make the first person wrong.
Note: I wrote another post about this topic called, “What if everyone followed their dreams? There’d be no garbage pickers!“