How do you KNOW all this stuff?

If I had a dollar for every time someone asked me how I had all this stuff in my head, I wouldn't have needed student loans for college.

It's a combination of things. One is that I read incessantly. If reading is physically impossible, or at least untenably risky, like when I'm walking somewhere, I have audiobooks and podcasts on my MP3 player. If I'm not reading, I'm working (which often involves Googling things like mad), or playing puzzle games (which often require me to recall things, or deduce things from clues I'm given), or writing (which requires me to regurgitate things which I have taken in via other methods). There's words around me all the time, and they say stuff. I try to parse out the useful ones.

Two is that I have an eidetic memory. I don't have a true photographic memory, where you can look at a random dot field and recall it while looking at another random dot field and tell the memory researchers leaning over you and probably already drooling over your test results what letter you see there -- I can't read large swaths of text off remembered pages, apropos of nothing. What I have is a contextually eidetic memory. Given the proper context, I can bring up mental preview snippets of stuff I've encountered before -- thumbnails of book pages or pictures, a snapshot of a room or a person, a few bars of a song, the cadence of speech and a few words -- and go through what I remember for details which I may not have consciously noticed at the time. It even works with movement and spatial orientation; I used to stock shelves overnight at a department store, and within a few days I could practically do it blind, because I 'felt' that those particular socks went on the shelf behind me, to my right, on the hook just above my shoulder level. It's not perfect, but because all of the preview snippets are stuck to a particular context (i.e., a particular bit of information), it means that once I remember one thing, I can usually follow the trail to others.

Which leads me to the third thing, which is that I don't actually know all this stuff in the conventional sense, but I know where to get at the information fast enough that it makes no practical difference. I don't know everything; I just know where to look everything up. Looked at from the proper perspective, the entire universe is just an external storage device for my brain -- unfortunately, the index is utter shit, and I spend most of my time trying to reconstruct it. I don't necessarily keep all the information per se in my head -- although I have enough in there that the family at one point banned me from playing Trivial Pursuit, on the grounds that it was unfair to the rest of them -- but I keep an enormous welter of links and cross-links and criss-cross-links and secondary and tertiary...

You know, I don't even know anymore. It used to drive my professors up a wall. I don't segregate the links according to the traditional boundaries of each school subject, so most of what I write is considered "cross discipline" in academia. Academics hate that, and in my less-charitable moments I wonder if that's because it means any conversation with me about things they've been poring over for the last forty years might wander into territory they're unfamiliar with. (It can get pretty scary when you're lost. I should know -- I spent my first few weeks in Boston wandering blindly around a city that was evidently laid out 400 years ago by bored cows, stumbling across parks and universities and T stops at random. It's even worse when it's mental.) As a defensive measure, I've developed a teaching style based almost entirely on analogy. Sometimes it helps, sometimes it doesn't; I still have to remind myself that analogies only work when the person I'm talking to knows one of the two ends, and I can't explain memetics by analogy to retrovirology to someone who knows neither.