The amount of data available to our senses is huge, and our awareness involves a great deal of selection. This first occurred to me when I was a child, waiting in an urban setting for my mother to come pick me up. I saw surprisingly many cars of the same model and color as my mother's car. Not because there was an extraordinary number of such cars but because I was looking for hers. Jung isn't inundated with fish in his essay on synchronicity; he's surrounded by the normal amount of fish, and suddenly he's aware of it. A fishmonger or supplier of a seafood restaurant living near Jung was used to noticing the same data and took it in stride, and might have been astonished if he'd had an inkling of how many books there were in their city, whereas someone like Jung would find nothing strange about it, having been focused upon books his whole life and having written and published books of his own since early childhood.
I like cities. I've spent a considerable amount of time both in big cities and in rural areas, and I much prefer the former, and that's in part because I'm a bookworm and I know where to get my hands on books inexpensively. I also know that if and when I become a rich and famous bestselling author, I will have many books sent to me for free by their publishers, all hoping to get some positive comment from me, each one of which they could convent into sales. Some of the volumes sent to me would resemble new hardcover editions in all but date -- I'd get them a little before the general public, so that if I made one of those positive comments they could change the dust covers to include it -- and some would be what are called review copies -- same pages as the hardcovers, with paperback covers containing remarks addressed to reviewers and bookstores. These same review copies and early hardcovers are sent to newspapers and magazines and websites, and are what their book reviewers read, and to bookstores.
The Bryn Mawr Classical Review publishes a monthly list of all the new titles they've received. And then people interested in reviewing these books, mostly Classics professors, contact Bryn Mawr. Whether the reviewers then keep the books, perhaps in lieu of payment, or send them back to Bryn Mawr, I don't know.
But chances are that I'm boring you to tears already, going into such detail about such things, because you are focused on whatever it is which trips your trigger and which you have made into your specialty. Perhaps, in the natural course of living your life the way you do, you just happen to have a very exact idea of how much paper currency is in that same metro area where I could tell you a thing or two about where the books are -- or perhaps you are more specialized, and know a lot about a particular foreign currency in a particular part of the US, or how many greenbacks of each denomination are currently in a particular region outside the US, or you might be an expert on newly-made mechanical watches, or antique pens, or steel wool, or plastic bottles of varous sizes, or socks, or pool hustlers (maybe as a fellow pool hustler, perhaps as a law enforcement officer, perhaps neither), or towels.
So, there's ten different categories of stuff -- cars, books, currency, watches, pens, steel wool, bottles, socks, pool hustlers, towels -- each of which could fill an entire rich and varied career, and some of those categories could be subdivided quite a few times and each one of those subcategories could still fill a life, and my mind reels when I even start to think about how many other such completely distinct categories there must be in any fair-sized city, all of them there in rich abundance all the time.
And I've just limited myself to cities so far. Cities are where the action would be for specialists in nine of those ten categories. A fish expert could be urban or rural. And for many categories, cities appear empty and boring, while the countryside teams with wildlife, if that's your thing (but of course there are also specialists in urban wildlife, it's more specialized but it is an existing career path), or large-scale agriculture (although urban agriculture is rapidly expanding at the moment).
You and I might be standing on a ridge overlooking an expanse of desert, and you might be a geologist, and perhaps you'd be excited because you knew that there a huge variety of crystalline quartz happened to be in and under the land we were looking at, and you might start to tell me about that, and start to get excited about the subject and go into great detail and begin to bore me greatly withing noticing or intending to. And then perhaps I might forget myself and interrupt you by remarking how few books there were for 100 miles in all directions, which in turn would bore and annoy you, and an expert on watches standing next to us might think we were both particularly tedious, and a nutritionist standing next to the horologist must find all three of us very boring, or completely fascinating, or might not be paying any attention at all to what any of us are saying, but instead closely examining our physical appearances and intently speculating upon our eating habits.
For a physicist, his subject matter is everywhere: city, countryside, in other galaxies, inside his head. For a theologian it's nowhere, but that hasn't stopped them yet. And whatever you're specialized in, for a living or for a hobby, you can take the point of view of a psychologist and examine the other humans and what they're examining. You never know when some other single organism will open up to you, and how rich and complex that opening might be.