- Some do, and we're really bad at figuring out which ones the are, especially ahead of time.
- It's a collective effort. Your thesis and my thesis might not be particularly groundbreaking or influential individually, but each one is a tiny step, more or less in the right direction, towards understanding something. It's mostly a myth that "geniuses" make huge leaps forward, while everyone else muddles around. Most ideas are presaged in the literature for a while before someone puts them together and runs with it.
The large majority of phds collect fewer than 20 citations. Most papers are ready by only a handful of people. "Screaming into the void" is a pretty accurate representation of many phds (including my own).
Working in industry and making money also contributes to humankind. Whatever the company is doing must be of some value in order to make money. So someone who may not have the right motivations to getting a PhD is probably better suited to move into industry sooner rather than later and be the most productive contributor to humanity as possible.
PhD's doesn't contribute new knowledge, they contribute knowledge that can't be proven to be old.
It might sound similar, but it is not. Let me explain the difference:
A person performs a study creating lots of data. If he wanted to contribute to human knowledge he would publish the data with no comments, as he is probably not the best person in the world to analyze this data. If on the other hand he was a PhD he would not publish the data, instead he would publish some pet theories related to the data so that he can build his brand, and most of all he will absolutely not publish the data since it could possibly be used to prove that his pet theories are not relevant or maybe even wrong which would be disastrous for his brand.
Now there are of course PhD's who do the right thing but it doesn't benefit their career at all.
I would argue that, while the pursuit of new knowledge is surely admirable, not all of it can be assumed to meet the high bar of being of "great value to history and humankind".
I can't speak for the person you replied to, but sometimes this is done as a way of disparaging money and the desire to have some, perhaps in the same vein as writing "Micro$oft".
- Some do, and we're really bad at figuring out which ones the are, especially ahead of time.
- It's a collective effort. Your thesis and my thesis might not be particularly groundbreaking or influential individually, but each one is a tiny step, more or less in the right direction, towards understanding something. It's mostly a myth that "geniuses" make huge leaps forward, while everyone else muddles around. Most ideas are presaged in the literature for a while before someone puts them together and runs with it.