All of those are true answers, but they're not really the answer. I'm a passive person; I don't make big life changes out of boredom. I knew I was giving up a lot in the way of excitement and material comforts, but most of the time I simply didn't care; even now that I have access to them, I'm not a big one for excitement or material comforts. And academia wasn't as much work as it could have been; as a theorist, I could do less work by being smart, and I always had other things in my life. So, while those things are all true, in the sense that I appreciate those benefits of being out of academia, they're not the reason that I left.
I was talking to a younger colleague today; after a couple years in the workforce, he's considering going to grad school for a PhD and wanted my take. I told him, honestly, that it's not always an easy life, even if it looks like one; that it requires dedication and focus and that your advisor has much more power over you than any supervisor in a regular job, and much less incentive not to abuse that power. I also told him that I though he's someone who would enjoy it, because he really is dedicated, and he's very good at what he does.
He asked me why I left, and I gave him the standard answers, and he didn't buy it. "You gave up doing research just so you wouldn't have to live in Idaho?" he asked, incredulous. This is a guy who should be getting a PhD, because to most people in this city, being able to live in New York instead of a tiny town in northern Idaho is reason enough to change careers. But then again, he's right, because when you love something, you follow it wherever it takes you, even to the middle of nowhere.
And then he told me what got him thinking about grad school: he was watching a documentary about waste disposal, and saw the marine biologists talking about the effect of trash on the ocean ecosystem. And he was thinking, these guys just get to be out there, on a boat in the middle of the Pacific Ocean, enjoying the sun, and they're improving the world. And meanwhile I'm a desk all day, trying to write better code so the company can make a little more money.
And he's right. Kind of. Those guys get to be out there on a boat, but they also have to be out there. They don't get to go home every night; instead they sleep in bunk beds and eat dehydrated meals. They don't get to see their spouses and children every day; if they're single, they have a hard time dating. They can't run five miles every day after work, as my colleague does now, and they're probably always smelly and wet.
But, sure, they're improving the world. Maybe, a little bit, sometimes. Not as much as they wish they were, and not as much as my colleague thinks Because that's the thing about academia, and maybe about all science - progress is slow, and frequently there is no progress. At a corporation, there are incentives to always be doing more, getting better, staying ahead of the game - even if those incentives are just money. But in academia, for everyone not working directly towards tenure, the incentives are fuzzier. Sure, yes, there's the drive to contribute to the world, to make a difference, to make it better. But that contribution will come in years, maybe a lot of years, maybe too many years for you to be around for, and it's a pitiful counterweight against the desire to go home, watch television, get some sleep. For really good scientists, the love of learning and exploration is the animating factor. For others, it's the desire for renown, or a sense that science is fun, or simply inertia. Or there simply is no motivation at all.
I had a difficult relationship with my work throughout my academic career. I was never as devoted to it as most people start out. I liked it, and I was good at it, and I have anything else I really wanted to do, and frequently that was enough. I liked learning new things that nobody else had ever learned. I liked assembling my work and discussing it with others. I liked reading papers and attending conferences. I had bad days, band months, even bad years, but so did everyone else. Whenever I got close to leaving, I told myself that I was doing something important, that I was making new knowledge, and that compared to this no job as a keyboard-presser was ever going to measure up, and that the joy of discovery outweighed the hassle.
After grad school, I spent two years as a postdoc in each of two groups. In the first group, I performed research with applications to drug delivery (how do we get drug molecules to the parts of the body - the cells, or the parts of the cell - that need them?) and separation mechanisms and the general area of nanofluidics. It's not a super-hot field, but it's an area of active research. The work I did had two distinct parts, and before I left I wrote up two papers, which - in accordance with standard practice - were to be revised and submitted in the next few months, while I ramped up work on my next project.
Except the papers didn't get revised and published. My former boss ignored them, and he ignored my emails asking about them, until after a year I submitted one paper without his assistance or approval and dropped the other. This wasn't just one bad experience; it happens all the time. Work isn't published because the student can't write, or the advisor is too busy or dislikes the researcher or has too many grants to write. During my nine-year career I spent at least four years doing research that was never published (that's four papers that I actually wrote, and a couple other papers' worth of research that never got written up) for reasons mostly unrelated to its quality.
In this case, the problem with my papers was that they were mundane; interesting and relevant work, but not exciting. My former advisor already had tenure and didn't need any more bread-and-butter papers. If he was going to be famous - which was the only place there was for him to go - he needed revolutions, and my work wasn't revolutionary. Most work isn't revolutionary. And most revolutionary work isn't as revolutionary as it sounds, either. Most of it is built on years or decades of small, quiet, incremental ideas and experiments and calculations that lead to a cataclysmic insight - or maybe just to a buildup of small, quiet, incremental ideas and experiments that are, as a whole, very important. But when those incremental findings don't see the light of day, when they're not published and not discussed, other scientists can't build on them. Nobody can do different or more specific work based on those findings, nobody can develop a theory to explain them or an experiment to test them, nobody can be inspired about a whole new line of thought. It's as if that work - that year or two years or four years of labor - never happened.
Work goes down the drain everywhere. My company could pull the plug on a project I'm doing that I think is useful and cool, and that would kind of suck, but I would accept it more easily. My job is fun and satisfying and remunerative, and if sometimes my work doesn't lead anywhere, well, eh. But in academia was job was less fun and less satisfying and way less remunerative; it was usually a slog, and it was frequently hellish in a variety of ways, and the payoff was knowing that I was doing something that really mattered. And when suddenly, because someone I used to work for was busy and absent-minded and not terribly fond of me, I realized that a lot of the work I had done was not going to matter at all, it was hard to accept the bargain I'd made.
I may not be improving the world now at my job, but at least I don't hate the world anymore, which is probably an improvement for the people around me, at any rate.