Yes, I should have added that scientists can get an early start on doing primary research, in large part because they're dealing with--I'm not sure whether this is the best way to put it--real time data. Most doctoral dissertations in the sciences are completed quickly, because if they aren't, someone else will beat the author to the punch, and he'll have to start over with a new project. Many scientists also peak at a relatively early age.
Perhaps rather than "authoritative sources", I should have said "reputable sources". When arguing a point, you need to know what's been said in the past. You may build on that work, or point out why the conclusions reached were incorrect. What I was getting at was simply that today's kids tend to accept whatever they read online, especially if it's what they'd like to believe. Every academic discipline is founded on a body--by now a very large body--of earlier serious work, and earlier not-so-serious work. What students need to learn is how to distinguish between those two categories, before they get down to figuring out where they stand on whatever issue they're attempting to deal with.
Science is not all the same. It doesn't necessarily deal in experiments, and sometimes history comes into it. Consider a problem like Fermat's Last Theorem. I have no clue what it's about, and probably wouldn't begin to understand it if it were explained to me. But obviously it was a seductive story; the proof Fermat said he'd worked out, but that had somehow been lost. Were subsequent attempts affected by changes in the field of mathematics over the next 350 years? That would be, from the point of view of someone like me, an interesting idea to pursue. And perhaps easier to deal with than arriving at the proof itself, though not by much. So count me out. But as far as I know, solving that kind of mathematical problem is no more "useful" than determining the year in which Leonardo da Vinci's portrait of Cecilia Gallerani was painted. (Something I was able to do; it was a whole lot less complicated.) It doesn't cure cancer, build better computers, or help us find better ways to make earthquake-resistant structures.
As for your philosophy professor, there are jerks in every field. Though the question of what makes man different from animals or machines (we really do want to believe we ARE different) is central to a philosopher's quest, there are and have been a great many, and widely differing answers offered. But you sensibly brought up Hawking. I don't think there's that much difference between philosophy, cosmology, and even religion. They all seek answers to that question: what makes us different; what makes us sentient; what are our origins; what is our destiny?
I have nothing to say about sociology, except that I think practitioners of the discipline should devote more of their time to the study of penny stock frauds and products hawked on late-night infomercials.
As for fashion, you're just plain wrong. Given that it's been around for millennia, I think we can assume it's hard-wired into us, and no doubt has to do with both mating rituals and expression of status. It's also fun. That doesn't mean everyone's into it, but we are, after all, individuals.
Art has spoken to people for millennia as well; it's even older than fashion. It's served people in many different ways, and what's endured for hundreds or thousands of years has done so for good reason. Like some of the rest of what I've been talking about, it an expression of who we are, what we believe, what we fear, what we dream. Just as literature does, it reflects the society of its time, and our interpretations of it reflect our own society.
Biographies of famous people--writers, artists, scientists, whatever--are only interesting if their lives were interesting. Some were; others--Bach's, for example--were not.
One of the great things about seminars is when a grad student asks some famous person to explain something about their presentation and it pokes a hole in the whole shebang - the big name dude is deflated by a 20 year old kid asking a question and he/she's at the podium and embarrassed and grasping for a recovery.
Happens in every discipline. Unfortunately it isn't a feature attendees can count on. It's much more usual for some wannabe to try to make his or her mark by standing up to ask a "question" designed to call attention to an idea cooked up by the wannabe that has nothing to do with anything the speaker had to say.