system
Given the following post, respond as if you're commenting on Reddit:
human
CMV: 'Jack of all trades, master of none' actually makes you worse at your profession

I'm a programmer who's interested in filmmaking. Far from being a polymath, I know, but I have been advised against it by people, reciting the old reliable "Jack of all trades, master of none" routine. I don't understand. Would tell polymaths such as Plato, Pythagoras, Newton, Da Vinci, and even modern ones such as James Cameron this? Some people believe in this so much that they limit themselves to their field, which might be extremely specialized. For example, would you trust a endocrinologist who doesn't know anything about psychiatry? All the diabetics go to him and he treats them like crap because "I'm not a psychiatrist, I'm an endocrinologist!" I had such doctor and I ditched him for a better one. That's not all. My new endocrinologist knows beyond medicine. He knows about psychology, philosophy, and even mathematics. That's what I like in my doctor: a polymath. Not someone like the last one who didn't know shit beyond his profession, and one might think this would have made him better at it... No, it made him worse at it. 

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I think anyone who coined the phrase "Jack of all trades, master of none" can go fuck himself. can you change my view?
gpt
The problem with your argument is that you used the word "profession." If you are running a new startup or working in a newly invented field, you want to be a jack of all trades. You never know what skill set you might need next. But if you are working in an old field with very clearly defined and refined needs, it's better to specialize in that thing. 

For example, doctors need to combine advanced scientific knowledge with humanist empathy. If they only have half that skillset, they aren't a good doctor. But they don't become a better doctor with other unrelated skills. 

Endocrinologists are taught and tested on psychiatry in medical school. They also have to have an understanding of psychology, philosophy, and mathematics just to get into medical school. All of those things you describe are part of their required skill sets. 

On the other hand, a polymath physician learns things that are completely unrelated. For example, being good at stamp collecting, long distance running, picking profitable stocks to invest in, etc. are all things that a polymath doctor might pick up. But they aren't something that would make them better at their profession (i.e., practicing medicine).